Major genes plus polygene mixed inheritance model and QTL IciMapping v2.2 Inclusive Composite Interval Mapping were used to study the genetic regulation of soybean fat content in F₂ segregating population materials of high protein Jiyu50 and high fat Jinong18 parents. The results showed that the soybean fat content trait complied with the polygenic inheritance model and was controlled by polygene. Polygene genetic rate was 79.15%. Two major effective QTLs and two micro effective QTLs on soybean fat content were detected and distributed in 12 (G), 17 (M) and 22 (F) 3 linkage groups, including a stable major QTL in two years.