Objective To analyze the difference among antigens of Angiostrongylus cantonensis in different developmental stages and identify dominant diagnostic antigen for angiostrongyliasis. Methods Antigens of A.cantonensis in different developmental stages were analyzed by SDS-PAGE and immunoblot. Results The protein bands of all developmental stages were similar on SDS-PAGE. The Mr 40 000 , 50 000 , 66 000 and 80 000 antigens reacted not only with the sera of rats infected by A.cantonensis but also with the sera of normal rats. The Mr 104 000 antigen could be discerned by sera of rats infected with A.cantonensis for 2 weeks. The Mr 32 000 antigen could be recognized by sera of rats 2 weeks after infection, and the reaction became stronger with the infection continued. Conclusion The Mr 40 000 , 50 000 , 66 000 and 80 000 antigens might result in the unspecific reaction in the immunodiagnosis of angiostrongyliasis using the crude antigen of A.cantonensis. The Mr 104 000 of larva, Mr 33 000 of adult females and Mr 32 000 of the worms might be used as candidate antigens in early diagnosis and epidemiological survey of angiostrongyliasis.