Abstract  [Aim]  To investigate the emergence and fecundity of Coccophagus japonicas Compere. [Methods]  Emergence behaviors, biological rhythms of emergence, as well as the effects of supplementary nutrients（mycose，melizitose，sucrose，honey，fructose and glucose）on the longevity and fecundity of C. japonicas were observed in the laboratory. [Results]  The emergence of C. japonicus can be divided into two stages; eclosion and adult hatching. The peak period of emergence was from 06:00 to 10:00. Supplementary nutrition affected adult life-span; the longest life-spans (15.58 and 14.97 d), were observed when supplementary sucrose and fructose were provided. The most eggs (236.50) were laid when supplementary sucrose was provided, whereas the least number of eggs were laid when glucose was provided. Peak oviposition occurred on the second day after emergence, after which oviposition decreased with adult age. Six-day old females produced the most offspring, after which offspring production significantly decreased with age. [Conclusion]  Six-day old, female C. japonicus are most suitable for indoor propagation and field release, and providing these with supplementary sucrose can enhance their productivity and biocontrol efficiency.