The product is a kind of white powder with decoloration processing, which is a hydrolysate prepared through high temperature and high pressure reaction by casein and hydrochloric acid, neutralization by sodium hydrate. The amino acid have showed with original form, which has high usage rate and is suitable for the composition of various culture medium. It is refined by hydrolyzed casein peptone, which is suitable for the growth and drug susceptibility test materials of diphtheria bacterium, bordetella pertusis, toxin of streptococcus pertussis and streptomyces. It is suitable for the culture medium of susceptibility testing and salt-tolerant microorganism. Total nitrogen (on DM) % 8.0%, Amino nitrogen (on DM) % 2.0%, Ash (on DM) % 6.0%, Moisture % 8.5%