Abstract: Two discrimination functions in terms of the length and the width of two types of Paragonimus westermani (diploid type and triploid type) obtained from northeast China are derived. One of them is used for discrimination of meiacercariae, the other for discrimination of eggs. The test results with independent samples from above areas, and Jiangxi Province and Anhui Province show that they could be used to differen tiate the above mentioned two types of P. westermani.