Abstract Moulting is of primary importance for all Crustacea, including the Decapoda. Properly dividing the stages of the moulting cycle is, therefore, a crucial prerequisite to explore the mechanism of moulting. In this paper, we studied the moulting stages in adult females of the freshwater Oriental prawn, Macrobrachium nipponense (De Haan, 1849), one of the major aquaculture species with a highly profitable value in mainland China. We divided the moulting cycle of M. nipponense into post-moult (stage A/B), inter-moult (stage C), pre-moult (stage D) and ecdysis (stage E), which were clearly to be distinguished by a combination of observation endpoints, including cephalothorax rigidity, internal cone formation in the setal lumen, pleopod epidermis retraction, new setal formation, epidermis invagination and cuticle formation. The pre-moult stage (stage D) was further divided into substages D 0 , D 1 , D 2 , D 3 and D 4 based on detailed endpoints such as apolysis, new setae tip emergence, papilla structure, extending of the invagination, double tubular sheath, extruding of the new setae rods, etc. In all, the results of this study provide a solid foundation for studying the moulting mechanism of M. nipponense , and can also be used as a practical method for distinguishing the moulting stages in the M. nipponense cultures.