Stem characters of 51 soybean materials were studied under normal light and shading conditions at seedling stage. The results showed that the coefficient of variation (CV) of soybean materials based on stem characters under normal light and shading were 8.40%-78.06% and 11.27%-84.68%, respectively. Except for CV for first and second internode length, CVs for other stem characters under shading were higher than that under normal light. Plant height, height of lowest branch and internode length were very significantly raised （P <0.01）, stem diameter, branch number and nodes of main stem were very significantly decreased under shading. Plant height index (IL)，internode length index( I2, I4 and I6) were significant among normal light and shading （P<0.05）. Correlation analysis showed that plant height was significantly positively correlated with every internode length (exclusion first internode length), and was not significantly correlate with nodes of main stem under shading. Path analysis indicated that the positively contribution of tenth, eleventh internode length to plant height was the largest under normal light, and that of seventh, tenth internode length to plant height was the largest under shading. Plant heights of six soybean materials were not significantly difference in two different light environments. Therefore, these results may play important role in soybean breeding of intercropping system.