The World Professional Billiards and Snooker Association announced the verdict on Monday, and is set to decide on the player's sanction at a separate hearing on Sept. 24. The 38-year-old Lee has been suspended since October last year and faces a possible lifetime ban.
The WPBSA said the Englishman fixed matches across four tournaments — the 2008 Malta Cup, the 2008 UK Championship, the 2009 China Open and the 2009 world championship.
Widely regarded as having the best cue action in the game, Lee has won five ranking events in his 21-year professional career.
It is the biggest case of match-fixing to hit snooker since Australian Quinten Hann was suspended for eight years in 2006.