In this paper, the effect s of methmidophos and phoxim with different concentrations and schedule on soluble protein content and chlorophyl a ( Chla) content in Porphyra haintanensis were studied under experimental and ecological conditions. The result s showed as follows: ( 1) there were some time-ef fect and dose-effect relationships between the pollutants and Chla contents. The Chla content of most of groups decreased with the increasing of do se and prolonging of the exposure time. In the same concentration, the toxicities of phoxim to Chla content was stronger than that of methmidophos. ( 2) All concentration groups in this study didn. t show the signif icant time-ef fect and dose-effect relationships between pollutants and the soluble protein. And there was no signif icant difference of the soluble protein content among various groups.