艾勤賢喺律政署做主控官嗰時，負責過「楊元龍造馬案」。私人執業後曾代表錢志明處理轟動一時嘅字母小姐案件。2002年8月，前冠軍騎師霍達被控造馬，佢做辯護大律師。
When Ai Qinyin was the chief prosecutor in the Attorney General's Chambers, he was in charge of the "Yeung Yuen Lung Horse Making Case". After his private practice, he represented Chin Chi Ming in the sensational Miss Alphabet case. In August 2002, former champion jockey Hoda was charged with building horses and he worked as a barrister.