In order to know the process of ovariole contraction after oviposition in Anopheles sinensis and An. Anthropophagus, and to determine the relationship between the ovariole contraction and the physiological age, the observation was conducted in 1988. The laboratory-reared female mosquitoes after 3-5 days of eclosion were fed with mouse blood and were kept in separate finger tubes for oviposition. After oviposition, the mosquitoes were dissected at different time. 30 ovarioles for each mosquito were examined and recorded by Detinova's method. A total number of 75 An. sinensis with 2,262 ovarioles and 87 An. anthropophagus with 2,591 ovarioles were examined after first oviposition. The duration for ovariole contraction in the phase of A,B,C,D,E was 1, 3-6, 9-14, 15-18 and 21h respectively. A total number of 40 An. sinensis with 1,337 ovarioles and 34 An. anthropophagus with 1,099 ovarioles were examined after third oviposition. The duration for ovariole contraction in the phase of A,B,C,D,E was 1, 3-9, 12-15, 18 and 21h respectively. E phase can be found in 21-24h after oviposition. There were 29.3% and 38.0% ovarioles in C and D phase for first oviposition while 48.4% and 46.0% ovarioles in C and D phase for third oviposition. It was found that the contraction occurred first in breadth and then in length.(ABSTRACT TRUNCATED AT 250 WORDS)