Four kinds of activating agents (WZ,SMS,MSN,FM) were used to promote the release of calcium-magnesium phosphate (PRCMPs).Continuous water extraction and potted corn were used to study the contents of water-soluble P,fertilizer effect and phosphorus efficiency of PRCMPs.The result of continuous water extraction indicated that the content of water-soluble P of PRCMPs was higher and more stable each time compared to calcium-magnesium phosphate.The accumulative rate of release increased from 22.5% to 51.8%.The result of potted experiments showed that the biomass of potted corn from four PRCMPs were much higher than that of calcium-magnesium phosphate.Compared to calcium-magnesium phosphate,the uptaking of P of PRCMPs was improved.The contents of Mg and chlorophyll of PRCMPs were high as well.Furthermore,the residual effects of PRCMPs increased.Compared to calcium-magnesium phosphate,the contents of water-souble P,biomass of sweet corns,phosphorus uptake and soil available phosphorus were higher.The use effeciency of phosphorus also increased.The effect of the second pot experiment was better than that of the first.Among the PRCMPs,the effect of PRCMP of SMS is the best.