【Objective】 Due to the differences in carbon chemical components among maize residue s(root, stem and leaf), their return to cropland soils with different fertility levels will induce differences in soil respiration and priming.【Method】 In order to explore these differences in the field, a 540-day in-situ field experiment with eight treatments of low fertilizer soil(LF+CK), low fertilizer soil + root (LF + R), low fertilizer soil + stem (LF + S), low fertilizer soil + leaf (LF + L), high fertilizer soil (HF+CK), high fertilizer soil + root (HF + R), high fertilizer soil + stem (HF + S) and high fertilizer soil + leaf (HF + L), was carried out at a long-term positioning station of brown earth in Shenyang Agricultural University using ¹³C labeled maize straw tracing method.【Result】 Results showed that (1) the contribution rates of soil respiration flux and straw carbon to soil CO₂-C emission showed downward trends over the in-situ incubation period. (2) Compared to the treatment without straw, the cumulative CO₂-C released from low fertility soil with root, stem and leaf increased by 134%, 126% and 95%, respectively, while that from high fertility soil increased by 157%, 189% and 96%, respectively. (3) The contributions of root and stem to soil CO₂-C emission in high fertility soil were significantly greater than that of leaf, but there was no difference in low fertility soil. (4) Different parts of maize straw returning to the field could cause the positive priming effects in both high and low fertility soils. Meanwhile, the priming effects of adding root and stem were significantly stronger than that of adding leaf, showing root and stem would cause more positive priming effects of soil CO₂-C than the leaf. Moreover, there was no significant effect on the priming effect between straw parts and soil fertility.【Conclusion】 Overall, this study enriched the theory of cropland soil respiration induced by straw returning, suggesting that the interaction of straw parts and soil fertility on soil respiration should be considered in straw returning.