Abstract: In order to explore the spatial and temporal characteristics of phytoplankton functional groups in Jingpo Lake of Heilongjiang Province, China, phytoplankton samples at 26 stations were collected in May, September and October, 2013.A total of 21 kinds of phytoplankton functional groups were identified:C, D, F, G, H1, J, L_O, M, MP, N, P, S1, S2, S_N, T, W1, W2, X1, X2, X3 and Y.The phytoplankton functional groups were dominated by D(shallow turbid waters), J(well-mixed, enriched shallow lakes), MP(frequently stirred up, inorganically turbid shallow lakes) and X1(adapted to frequently stirred up, inorganically turbid, and eutrophic shallow lakes) based on the dominant degree(>0.02).Significant differences were found on phytoplankton functional groups in different stations in the three investigations.The successional law of phytoplankton functional groups in different seasons could be summarized as D+MP+X1+X2 in May, X1+P+MP+L_O+J in September, and X1+P+MP in October.Principal component analysis was applied to determine the major potential stressors affecting the habitat of phytoplankton by SPSS 13.0, and canonical correspondence analysis was used to explore the relationship between phytoplankton functional groups and major environmental parameters.The results showed that water temperature(WT), dissolved oxygen(DO), transparency(SD), electric conductivity(EC), permanganate index(COD_Mn) and ammonia nitrogen(NH₃-N) were the most important factors influencing the distribution of phytoplankton functional groups across the 26 sampling stations.