[Aim] As an important ecological factor, temperature profoundly affects the distribution of Bursaphelenchus xylophilus. We studied the response of B. xylophilus to low temperature and the mechanism of its ecological adaption.[Method] In this study, fraction quiescent, free sugars, polyols and ascarosides contents were measured after the B. xylophilus had been treated at 25℃ and 4℃ for 48 hours. We also investigated the effects of ascarosides on fraction quiescent at 25℃.[Result] The fractions of quiescence of all ages, including L₂, L₃, L₄ and adult worms of B. xylophilus, significantly increased at 4℃ compared to the control at 25℃. Trehalose content was 2.32 times than the control, while sorbitol, glucose and glycerol did not significantly differ from the control. The analysis of ascarosides showed that the contents of C5, C6 and ΔC6 decreased, C7 and ΔC9 secretion ceased, while C9 began to secrete at 4℃. Simultaneously, bioassay showed that crude extracts containing C6, C7 and C9 significantly increased the fraction of quiescence at 25℃.[Conclusion] Several ascarosides were involved in the regulation of stress-induced sleep at low temperature in B. xylophilus.