Diapause is a complex and dynamic process. Chilo suppressalis, an important rice pest in Asia enters facultative diapause as larvae. Our results demonstrated in Yangzhou, China, diapause was initiated between September 4 and 12, 2010. After diapause termination, C. suppressalis remained in quiescence in the field for as long as three months. The average time between collection of field larvae of C. suppressalis and their pupation decreased as the season progressed from fall to next spring. Unexpectedly, the pupated ratio of female to male in the initiation of diapause was 0.22. The abundance of hsp90, hsp70, hsp60 and CsAQP1 all peaked on January 8 or 15, 2011. Nitric oxide (NO) is a secondary messenger that is positively correlated with the diapause of C. suppressalis. Among several geographically separated populations of C. suppressalis, there are no significant differences in the mRNA levels of hsp70, hsp60 or CsAQP1.