Ovomermis sinensis (Nematode,Mermithidae) is a parasitic nematode of ar myworm. But during its culture in vitro and rearing in vivo, we found that we co uld not attain the suitable proportion of male and female nematodes. In order to disclose the reason why the number of the filial generation was imbalanced betw een two sexes and get basic data on genetic development, we analyzed dissoluble proteins of Ovomermis sinensis imagoes with electrophoresis. Firstly, throug h SD S-PAGE, we found more than three specific proteins were detected in female imag o with the approximate molecular weight of 15-16 kD, 21-24 kD, 72-76 kD and on e abou t 26 kD specific protein in male imago. Secondly, we used a new improved two-di me nsional electrophoresis method to analyze the proteins and found that the result acco rds with those of SDS-PAGE, which showed that this 2-DE method is practicable. A lso, in this 2-DE, proteins can be well separated and plenty of different pr oteins can be clearly displayed .