Abstract: Accumulation patterns of grain protein and fat during reproductive development of three soybean genotypes different in protein content were investigated.The results showed that the peak of relative content accumulation in fat appeared at 30 days after R₅ stage in all cultivars (line),but with little difference in accumulation pattern,the lower protein cultivar(line) performed lower fat accumulation ability even at initial stage of accumulation,the pattern and peak of protein accumulation showed significant varietal differences, the accumulation patterns of absolute contents of protein and fat were similar in all cultivars used and the accumulations of absolute contents of protein and fat in higher protein cultivars were mainly influenced by the curve of single grain weight,however,lower protein line was influenced by relative content.