Abstract: Fish scale,rich in collagen and calcium,can be used as the raw material of producing collagen products and calcium supplements. In order to improve the comprehensive utilization and eliminate the pollution to environment from fish scale,the joint production technology of calcium citrate,collagen and collagen peptide was studied.The optimized de- ashing process parameters were ultrasonic power 120 W,ratio of material to water1∶ 20 g / m L,citric acid mass fraction 6%,processing time 180 min,as the de- ashing rate of grass carp scale,silver carp scale and sardine scale could reach 97.8%,97.6% and 98.1%,respectively. After de- ashing,pepsin hydrolysis assisted by ultrasonic was used to extract collagen from fish scale,the optimum extraction conditions were as follows: ultrasonic power 180 W,ratio of material to water 1∶ 20 g / m L,enzyme dosage 2000 U / g,extraction time 8 h.Under this condition,the collagen extraction rate of grass carp scale,silver carp scale and sardine scale was 40.1%,42.2% and 56.2%. Scale residue after extracting collagen was directly used for collagen peptide preparation,the optimum conditions were as follows: substrate mass fraction 5%,enzyme dosage 280 U / g,the p H value of 2,processing temperature 65 ℃. Under this condition,the collagen extraction rate of grass carp scale,silver carp scale and sardine scale reached 91.7%,89.3% and 88.9%. Eventually,the joint production technology was verified and the result showed that the established joint production technology was stable and reliable,and might pave the way for industrial production.