[Objectives]  To determine the developmental stages of Grapholitha molesta (Busck) larvae and provide a foundation for forecasting and scientific management of this pest. [Methods]  Four morphological variables were measured, including larva head capsule width, mandible width, body length and head width. [Results]  Head capsule width and mandible width conformed to the Dyar and Crosby rules, as well as having an obvious linear relationship, making them important criteria for identifying larval instars. The duration of the larval stage was about 15 d when reared under laboratory conditions at 26℃. Five Grapholitha molesta larval instars could be distinguished. These were; first instar (1-4 d), second instar (4-7 d), third instar (6-10 d) , fourth instar (8-12 d), fifth instar (11-14 d). [Conclusion]  Bristles, body color and markings can be used as auxiliary distinguishing criteria method when body length and width were too variable to reliably identify instars.