Abstract: The solid-state fermentation by microbes was optimized by using response surface analysis(RSA)with JMP staTIStical software．A polynomial regression model including the four major factors(feed to water ratio，cottonseed meal usage，fermentation duration，temperature) was set up．The results showed that the optimal fermentation condition was as follows：cottonseed meal 10．1％ ，temperature 30．1℃ ，feed to water ratio at 1：0．8，fermentation for 46 ．9 h，in which the crude protein content was increased to 41．7％, exceeding 15．8％ than before．

Key words: response surface analysis(RSA), rapeseed meal, solid-state fermentation, crude protein