The mixed major-gene plus polygene inheritance model was used to analyze the genetics of leafblade-weight and petiole-weight trait in SI×Qiu017 of non-heading Chinese cabbage. The results showed that the leafblade-weight trait was controlled by one pair of negative complete dominant major genes plus additive-dominant polygene (D-4). The additive effect in the major gene was 1.8991, the dominant effect was -1.8991; the additive effect in the polygene was -1.2934, and the dominant effect was 1.7933; the potential ratio was -1.3865, and the dominant degree was -1.0000; the heritability of the major gene was 6.98% in B1 generation, 4.33% in B2 generation, and 36.08% in F2 generation; the heritability of the polygene was 16.03% in B1 generation, 7.39% in B2 generation, and 23.96% in F2 in the leafblade-weight trait. The peti-ole-weight trait in SI×Qiu017 was controlled by one pair of additive major genes plus additive-dominant polygene (D-2). The additive effect in major gene was -1.1457, the dominant effect was 0.0000; the additive effect in polygene was 1.3472, and the dominant effect was 2.5788. The potential ratio was 1.9142, and the dominant degree was 0.0000; the heritability of the major gene was 31.72% in B1 generation, 5.27% in B2 generation, and 57.94% in F2 generation. The heritability of the polygene was 0.42% in B1 generation, 4.59% in B2 generation, and 4.80% in F2 in the petiole-weight trait. The improve-ment of leaf-weight trait of SI×Qiu017 should be selected in late generation, and the improvement of petiole-weight trait of SI×Qiu017 should be selected in early generation.