Abstract: Chondroitin sulfate was extracted from sturgeon cartilage by alkaline and enzyme hydrolysis. The technical conditions of extraction were optimized on the basis of former experiments. The results showed that combination of alkaline and enzyme hydrolysis could give a higher purity for chondroitin sulfate product. The optimal parameter was as following:raw material was mixed with 10 times of 6% NaOH (m/v) and extracted at 40℃ for 10h, then added 1% trypsin after pH was adjusted to 7 with chlorhydric acid solution and extracted at 50℃ for 8h. Denature of enzyme was performed at 95℃ for 5min, chondroitin sulfate was precipitated for 8h at 4℃ with 1.25 times 95% alcohol and the precipitate was dried in oven at 45℃ . Under these conditions, the extraction yield was 16.65% and the content of aminohexose was 17.35%.