The optimum conditions for pig bone extract fermented by Monascus were studied in the first part of the paper,as well as the change of protease activity,degree of hydrolysis,soluble nitrogen,peptide-based nitrogen and amino nitrogen in various fermentation period.The results showed that: The optimum conditions were substrate concentration 3%,temperature 30℃,shaking speed 120 r/min,the natural pH(6.7~7.0).The enzyme activity and degree of hydrolysis were up to their max on the 5th day,respectively,35.92 U/mL and 38.66%;Free ammonia nitrogen content increased gradually during the fermentation process,which become stable after 5 days.Peptide-based nitrogen content decreased slightly to a certain value,and finally to a maximum of 74.21% on the 5th day.Soluble nitrogen content in the initial stage of growth declined slightly,also to reach its maximum content of 88.45% on the 5th day.Electrophoretic analysis showed that the protein molecular weight gradually decreased during the six-day fermentation,and the minimum was 8.1kDa after 6 days.