就长江口海区一次骨条藻 (Skeletonemacostatum)赤潮发生过程 (1990年 6月 9～ 15日 )的环境因子与赤潮生物量数据 ,运用SAS软件 ,进行多元统计分析。结果表明 :赤潮发展与维持期的环境因子呈相似性 ;赤潮消亡时 ,水域环境因子向正常水平恢复。相关、变量聚类及主成分分析三种方法求得的结果基本一致 :影响本次赤潮形成的重要因子是气压、水温、盐度、pH、NO-3 N、PO3-4 P与Fe。逐步回归分析确定了盐度、PO3 -4 P与Fe是本次赤潮形成的主导因子 ,同时建立了赤潮的线性判别函数。选择长江口另外一次骨条藻赤潮发生过程(1990年 8月 11～ 2 2日 )的环境因子数据进行赤潮判别 ,结果令人满意 Environmental factors and red tide biomass data of the primary red tide of Skeletonema costatum in Yangtze River estuary area (June 9 ~ 15, 1990) were analyzed by multivariate statistical analysis using SAS software. The results showed that the development of red tide was similar to the environmental factors during the maintenance period. When the red tide died, the environmental factor of the water area recovered to the normal level. Correlation, variable clustering and principal component analysis. The main factors affecting the formation of this red tide are air pressure, water temperature, salinity, pH, NO3N, PO3-4P and Fe. Stepwise regression analysis confirmed that salinity, PO3 -4 P and Fe were the dominant factors for the formation of this red tide, and at the same time established a linear discriminant function of red tide. The selection of environmental factors data of the red tide from another Skeletonema algae in the Changjiang Estuary (August 11 to August 22, 1990)