[Aim]  To investigate the effect of indirect external force on thanatosis in Calospilos suspecta larvae, and on the subsequent growth and development of larvae. [Methods]  Buxus megistophylla branches on which C. suspecta larvae were crawling were impacted by 3 N forces (1, 2, 3 and 4 impacts a day respectively, for 4 d, or one impact a day, for 1, 2, 3 and 4 d respectively). The thanatosis characteristics of larvae and their pupal weight were then statistically analyzed. [Results]  (1) There were significant difference in the frequency of thanatosis among the different treatments (P<0.05). The frequency of spinning thanatosis decreased with increased frequency of impacts but was significantly higher than that of landing thanatosis after the same number of impacts (P<0.05). There were significant difference in the return time, and the length of silk, in spinning thanatosis among the different treatments. There were also significant difference in pupal weight among the different treatments (P<0.05). Female and male pupal weights were higher in treatment than in the control groups (The control group had no external impact, The weight of female pupal: 0.102 g, The weight of male pupal: 0.088 g). (2) There were significant difference in the frequency of landing thanatosis, the return time of spinning thanatosis, and pupal weight, among different treatments when branches were impacted once a day for a different number of days (P<0.05). The frequency of spinning thanatosis was also significantly higher than that of landing thanatosis when branches were impacted once a day for the same number of days (P<0.05). [Conclusion]  The effect of indirect external force on larval thanatosis in C. suspecta varied with impact frequency and the number of trial days. The frequency of spinning thanatosis was higher than that of landing thanatosis in all treatment groups. Larvae subjected to indirect force tended to have higher pupal weight than those in the control groups.