Abstract: Parasitoid wasp is an important biological control agent of insect pests. Development regulation is important in extending shelf life, improving control efficiency and timing release. Most parasitoid wasp species enter diapause as prepupa or larva, and some as pupa or adult. Analysis of diapause in 127 parasitoid species showed that: (1) Photoperiod and temperature are the main factors influencing diapause of parasitic wasps, host and nutritional status can also exert influence. (2) The stage right before diapause stage is usually sensitive to diapause signal. (3) There is maternal effect in some species, their offspring are more stress-resistant. (4) It is possible to extend shelf life by diapause and the storage period can be as long as 16 months. (5) Diapause termination can improve biological control efficiency of the current generation of parasitoids and their F1 offspring, but also increase parasitoid mortality. An outlook of further research on diapause of parasitoid wasps is suggested.