Lymantria nebulosa (L. nebulosa) Wileman larvae were collected from the natural secondary forest of maple tree in Yuelu District in Changsha and Xiangxiang of Hunan province at mid–late May 2017, and raised indoor. The morphological characteristics and the developmental stages were observed and recorded in the laboratory. Our results showed that the larvae visual toxic burrs gradually became bigger and poison gland color gradually deepened; the head capsule width was considered as the best index and the body length and body width could be used as auxiliary indexes for separating larval instar. L. nebulosa larvae have 7 instars when raised at 27 ℃, and it took about 66.7 days to complete one generation, with the ratio of female to male 0.965 5 and the fecundity (330.43± 27.801) per female.