In order to understand the composition and quantitative variation of ecdysteriods in the pu- pae of Opogona sacchari (Bojer), a new invasive alien pest, we analyzed the pupal ecdysteroid com- position and titers in this pest. The main component of ecdysteriods in the pupae of O. sacchari is 20-hydroxyecdysone. The titre of ecdysteriods in both male pupae and female pupae get higher gradually, and then decreased slowly after reaching a peak (80 ng/pupa). The titre of ecdysteriods was about 30 ng/pupa in the later stage of pupae. The peak of male pupae appeared on the third day, but the peak of female pupae lasted from the second day to the fourth day during pupal developments. The ecdysteroid content was higher in female pupae than in male pupae during specific pupal time (the 1st, 2nd, 4th, 5th, 6th day). We also found that the titre of ec- dysteroids in posterior part of pupae was higher than in anterior part of pupae obviously. In order to understand the composition and quantitative variation of ecdysteriods in the pu-pae of Opogona sacchari (Bojer), a new invasive alien pest, we analyzed the pupal ecdysteroid com- position and titers in this pest. The main component of ecdysteriods in the pupae of O. sacchari is 20-hydroxyecdysone. The titre of ecdysteriods in both male pupae and female pupae get higher gradually, and then decreases slowly reaching reaching a peak (80 ng / pupa). The titre of ecdysteriods was about 30 ng / pupa in the later stage of pupae. The peak of male pupae was on the third day, but the peak of female pupae lasted from the second day to the fourth day during pupal developments. The ecdysteroid content was higher in female pupae than in male pupae during specific pupal time (the 1st, 2nd, 4th, 5th, 6th day). We also found that the titre of ec- dysteroids in posterior part of pupae was higher than in anterior part of pupae obviously.