Abstract: Based on field observation and indoor study on the eclosion rhythm characteristics, the difference in eclosion process from 1st to 4th generation, the statistics of eclosion rate and the eclosion period of generations were investigated. The factors impacting eclosion were analyzed by orthogonal experimental design. The results showed that the eclosion of Micromelalopha sieversi (Staudinger) showed the "hump" rhythm characteristic, one peak at 4:00 and another one at 17:00. There were differences in eclosion process from the first generation to the 4th generation under the same condition. The period in which 80% eclosion finished became shorter in every generation, and so was the interval of peak between the male and female emergence in the same generation. The average emergence rates among first generation to 4th generation were significantly different which were (31.41±1.16)%, (43.67±1.84)%, (38.20±1.39)% and (27.81±2.42)% respectively. The development durations among first generation to 4th generation were also significantly different which were (10.71±0.45), (8.56±0.17), (6.88±0.68) and (6.43±0.66) d respectively. Statistical results verified that the eclosion rates were significantly difference among different temperature and relative humidity treatments, but not among the different photoperiod treatments. The best temperature of photophase was (30±1) ℃, and the dark period temperature was (24±1) ℃, and the humidity were photophase (50±10)%, dark period (70±10)%.