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In order to explore possible development process of red tides caused by Prorocentrum donghaiense, effects of concentrations of P. donghaiense and Oxyrrhis marina on the feeding behaviour of Oithona brevicornis were investigated. The results showed that within the concentration range of P. donghaiense, 1.0~5.0×104 cells·mL-1, ingestion rates (IRs) and faecal pellet production rates (FPPRs) of O. brevicornis on P. donghaiense increased with increasing concentrations of P. donghaiense, the maximum IR and FPPR were 620 cells·ind-1·h-1 and 31.67 pellet·copepod-1·d-1, respectively. When the concentration of P. donghaiense was 10.0×104 cells·mL-1, the IR value decreased to 400 cells·ind-1·h-1 and the FPPR value decreased to 13.33 pellet·copepod-1·d-1, respectively. Within the concentration range of P. donghaiense, 1.0~10.0×104 cells·mL-1, filtration rates (FRs) of O. brevicornis decreased with increasing concentrations of P. donghaiense. The results also showed that O. brevicornis could ingest O. marina fed P. donghaiense, and within the concentration range of O. marina, IRs of O. brevicornis on O. marina increased with increasing concentrations of O. marina, while its FRs decreased, the maximum IR value and FR value were 300 cells·ind-1·h-1 and 0.23 ml·ind·h-1, respectively. Within the concentration range of O. marina, FPPRs of O. brevicornis increased with increasing concentrations of O. marina, the maximum FPPR was 21.67 pellet·copepod-1·d-1, and FPPRs had a good linear relationship with IRs. In this study, "Copepodsred tide algae" and "Copepods-protozoa-red tide algae" food chain models can provide references for the development process and regulating method of red tides caused by P. donghaiense. [ABSTRACT FROM AUTHOR]