In this study，the soybean cultivar“Hefeng50”of the Sanjiang Plain of the Heilongjiang province was used to study the effects of the foliar application of nitrogen at different growth stages on the chlorophyll content and dry matter accumulation of the soybean plant.The results showed that when 5.0 kg·hm-2of nitrogen was applied at the V5 stage，the chlorophyll content，as measured by the SPAD value，was 56.4，and the no seed dry matter accumulation was 26.4 g.When the same treatment was applied at the R5 stage，the seed dry matter accumulation was 25.0 g，which was higher than that of all other treatments.Therefore，“Hefeng50”has the highest yield under the condition of 5.0 kg·hm-2of leaf nitrogen application at R5.