Upon graduation from secondary school, Lui Si-lan joined the Guangzhou Songs and Dances Troupe as professional vocal actress. She joined the HKRep as full-time actress in 1983 and appeared in over 70 productions, in which some were leading characters, including the 15 years old Form Three student Heung Mei in Before the Dawn Wind Rises, the Native American woman in Black Elk Speaks , Empress Dowager in De Ling and Empress Dowager Ci Xi, Ming Chun in Forever And Ever (First run and re-run) and Aase in Peer Gynt.

She also appeared in The Empress Dowager, The Story of Ah Q, The Importance of Being Earnest, Noises Off, House of Blue Leaves, The Matchmaker, Other People's Money, Guan Hanqing, King Lear, A Midsummer Night's Dream, Villa Parasol, Cat On a Hot Tin Roof, The Imaginary Invalid, Oedipus the King, Hong Kong for Sure!, A Night in the Kitchen and Whose Life Is It Anyway?.

Lui also appeared in several musicals, including Polly in The Threepenny Opera and Zhu Xiu Lian in Guan Hanqing in which its excerpts of The Injustice Done to Tou Ngo was supervised by celebrated Kunqu Opera artist Ms Deng Yuanxia.