Abstract:With the shell powder earned from waste shells as a calcium source，compound amino acids chelated calcium consisting of L-histidine and L-arginine were simultaneously prepared by the synthesis method in a watery solution.Using the chelation rate as a sign，single-factor and orthogonal experiments were designed to explore the effects of the molar ratio of compound amino acids to shell powder，pH，temperature，time，and others on the chelation rate.The results showed the ideal chelation conditions were as follows:the compound amino acids-shell powder molar ratio of 1∶1，the reaction time of 60 min，the reaction temperature of 50 ℃，and the solution pH of 9.Under these conditions，the compound amino acids chelated calcium showed the highest chelation rate.This study provides a new idea for the high use of waste shell powder and the preparation technology of compound amino acids chelated calcium.