Abstract: A water culture experiment was conducted to study the responses of 11 southern spring soybean cultivars to low phosphorus stress and the correlation between acid phosphatase activity (APA) and low phosphorus tolerance of these cultivars. The experimental results showed that dry weight of shoot. dry weight of root, total phosphorus (P) and nitrogen (N) contents of plants among these cultivars were significant differences (P0. 01) under low P condition. As the differences, it was thought that low-p tolerance of soybean cultivars was significant difference. The correlations of dry weight of shoot, dry weight of root, total P and N contents of the cultivars with their APA reached significance levels (P0. 05 or P0. 01). APA was relation to low-p tolerance of soybean cultivars. and it could act as a blochemical index for screening low-P tolerant soybean cultivars.