In order to develop and use small black soybean resources, improving grain yield, we studied the effect of different row and plant spacing (density) on coefficient of variation of yield and relative characteristics of small black soybean with randomized block design in Xi County of Shanxi Province. The results showed that, the average grain yield of 40 cm row spacing was better than that of 60 cm row spacing, and in different row and plant spacing (density) patterns, the grain yield, grain yield per plant, pods number per plant and pod setting height with R40P30 (plant number 8.34×104/hm2) treatment were superior to those with the other mothers, 100-seed weight with R60P15 (plant number 11.12×104/hm2) treatment was optimal, plant height with R60P25 (plant number 6.67×104/hm2) treatment was the most, and all treatments hadn’t influence on effective branch character. The influence of different row and plant spacing patterns (density) on various characters coefficient of variation was grain yield > pod setting height > grain yield per plant > 100-seed weight > pod number per plant > effective branch > plant height. Thus this research provided the theories and technical support for the further increase grain yield of small black soybean.