Liu was arrested on August 31 in the US state of Minnesota after an allegation of rape and was released the following day without charge and without paying bail, but remains under investigation by US police. He has, through his lawyers, denied any wrongdoing and returned to work in China.
A spokeswoman for the e-commerce giant said Liu would not attend the forum, but did not elaborate on the reason why. The event will run from Monday to Wednesday. Liu's name had been printed in the program and he had been named as a speaker.
US-based lawyers for Liu could not immediately be reached for comment on Monday.
Since returning to China, Liu has appeared at small signing events on behalf of the company but is yet to attend a high-profile public event.
The Shanghai forum is hosted by China's National Development and Reform Commission as well as its industry and cyberspace ministries, and is aimed at showcasing China's growing prowess in artificial intelligence.