Abstract: The distribution of phytoplankton in the Western Pacific Ocean showed different responses to the climatic changes under different temporal and spatial scales. This paper is aim to explore how Chl a，SST and nutrient respond to longterm climate change by data analyzing and use of literatures. Here we establish a preliminary conceptual model for the responding to climate change. The correlations among Chl a in different regions of the Western Pacific Ocean and the climate change related factors， such as SST and seawater nutrient （nitrate）， were examined. The results show that at site K2， Chla is positively correlated with SST and nitrate， which may relate to the upwelling in this area， while at sites S1 and XT， they show negative correlations of Chl a with SST and nitrate， which may relate to the intensified stratification and the decrease of nutrient input caused by the increase of SST. The selection and validation of model parameters laid a foundation for further improvement and optimization of climate change responding model of the phytoplankton changes in the Western Pacific Ocean．