Objective To study the water quality and the growth and metabolism of young Apostichopus japonicus in closed recalculating aquaculture system.Method Feeding different microecological preparations in the closed recalculating aquaculture system at(16±1)℃.Result The 30 days experiment result showed that the closed recalculating aquaculture system had a certain self-purification ability and the microecological preparation could significantly extend the cycle of the self-purification system.The EM probiotic agent had an advantage in controlling dissolved oxygen.The multi-strain agents Haiwei and NEM had better purifying effect on TNH3-N,TNO2-N,TPO4-P,COD and the metabolism of Apostichopus japonicus than the single-strain EM probiotic preparation.In addition the NEM can significantly improve the growth rate of the Apostichopus japonicus.Conclusion Microecological preparations can improve water quality and significantly enhance the metabolism and growth of young Apostichopus japonicus.