廖秀冬喺1988年開咗一間環境顧問公司，同政府、學校同埋建築師、發展商等私人機構提供對環保事項嘅專業意見。1997年，佢間公司仲同一間國際工程顧問公司合併而開始涉及中國內地同臺灣方面嘅範疇。2001年北京申請辦2008年奧運會，廖秀冬畀奧運會申辦委員會請咗做環保專家同代表，負責同北京申辦奧運講解環保狀況嘅部份。佢都做過西圖集團中國區總經理，負責管理環境同基建工程。2002年7月，當時嘅行政長官董建華推行高官問責制，搵咗廖秀冬做環境運輸及工務局局長。
In 1988, he set up an environmental consultancy to provide professional advice on environmental matters to the government, schools and private organisations such as architects and developers. In 1997, his firm also merged with an international engineering consulting firm to cover Chinese mainland and Taiwan. In 2001, when Beijing applied to host the 2008 Olympic Games, Liao Xiudong invited environmental experts and representatives to the Olympic Bidding Committee, who was responsible for explaining the environmental protection status with Beijing's bid for the Olympic Games. He was also the General Manager of Citule Group China, where he was responsible for environmental and infrastructure projects. In July 2002, the then Chief Executive Tung Chee-hwa implemented the accountability system for senior officials and hired Liao Xiudong as the Secretary for the Environment, Transport and Works.