Up to 40% of goods Venezuela subsidises for its domestic market are smuggled to Colombia, where they are sold at much higher prices, the authorities say.
The border was closed on Monday night, and will be each night for a month.
The move has been agreed with the Colombian government.
The Venezuelan government initially announced that it planned to close the 2,200km-long (1,360-mile) border every night for an indefinite period.
But later the general in charge of the operation, Vladimir Padrino Lopez, clarified that the ban will be lifted after a month.
The border is being closed between 22:00 local time (02:30 GMT) and 05:00 (09:30 GMT).
Cargo vehicles, including vans and lorries, will be banned from crossing from Venezuela to Colombia between 18:00 (22:30 GMT) and 05:00 (09:30 GMT).
Venezuela, which has the world's cheapest petrol prices, estimates 100,000 barrels of petrol are smuggled through its western border every day and sold illegally in Colombia.
The 17,000-strong contingent "will be enough to guarantee security" along the border, said Gen Padrino Lopez.
The governor of Venezuela's western state of Tachira, Jose Vielma Mora, said that regional leaders support means the measure will be effective.
"There is plenty of evidence to show that most of the smuggling is done overnight," he told El Universal.
Dissatisfaction with the shortage of many staples, as well as rampant crime and high inflation, led thousands of people in the western Venezuelan states of Tachira and Merida to take to the streets in January.
The protests quickly spread to the rest of Venezuela, which faced similar problems.
The opposition blames failed left-wing policies of the past 15 years - initiated with the late president, Hugo Chavez - for the country's economic crisis.
The smuggling of cheap goods from Venezuela is also seen as a major problem in Colombia.
The Colombian government says it leads to a big loss in taxes and complaints of unfair competition by local businesses.
The profits from are often used to finance drug gangs and left-wing guerrillas, says the BBC's Arturo Wallace in Bogota.
President Nicolas Maduro discussed the measures with his Colombian counterpart, Juan Manuel Santos, at a summit on 1 August.

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Ryan Giggs was the favourite following Bob Bradley's exit on Tuesday, but the club are now looking elsewhere.
Wales boss Chris Coleman was also a target but is out of the running.
Clement was interviewed for the job in October before Bradley replaced former head coach Francesco Guidolin.
The former Derby County manager, who was sacked by the Rams in February, has spoken to the Swansea hierarchy having impressed them in the autumn.
Rowett, meanwhile, has not taken on a job since his sacking by Birmingham City earlier in December.
The Swans are hopeful of having Bradley's replacement in place before the trip to Crystal Palace on 3 January.
Alan Curtis, who is taking temporary charge of the team, believes the club's next manager should be British and have experience of the Premier League.
"It has to be the right man. Ideally they would be British and know the Premier League," Curtis said.
"[The owners] have to be satisfied he fills all the criteria for getting us out of the trouble we find ourselves in."
Former Swansea forward Curtis, who is preparing for Saturday's home game with Bournemouth, says he has spoken to chairman Huw Jenkins but does not know how long he will be in charge.
"We will take it on a day by day basis," he continued.
"What the club needs is not a change of direction. The club has been the club and the way we run the club is the way that suits us.
"Somebody needs to come in with our philosophy with a little bit of experience and perhaps look at it with fresh eyes. That's exactly what it needs."
Venezuela says it has deployed 17,000 troops along its border with Colombia, which was closed on Monday for the first time as part of an anti-smuggling operation.
[NEXT_CONCEPT]
Bayern Munich assistant manager Paul Clement is the leading candidate to become Swansea City's new manager - but former Birmingham City boss Gary Rowett remains in contention.