Abstract: To investigate the effects of replacing chemical fertilization with organic manure on black soil quality and maize yield under different tillage practices in the Northeast Black Soil Region, this study utilized a long-term conservation tillage experiment (established in 2012 with full straw return) at the Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences. With partial substitution of chemical fertilizers by organic manure (accounting for 20% of the nitrogen input), four treatments were designed: no-till with partial organic manure replacement (NTSM), no-till with chemical fertilizer only (NTS), conventional tillage with partial organic manure replacement (CTSM), and conventional tillage with chemical fertilizer only (CTS). Soil physicochemical properties and maize yield were examined. Results show that, with the exception of total soil nitrogen, available nitrogen, and total phosphorus, soil organic matter and nutrient content follow the pattern: NTSM>NTS>CTSM>CTS. In comparison to chemical fertilizer-only treatments (NTS and CTS), organic manure substitution treatments (NTSM and CTSM) increase soil organic matter, available phosphorus, and available potassium by 7.11% and 2.17%, 2.41% and 26.4%, and 17.8% and 4.80%, respectively, while raising the pH by 0.67 and 0.28. Statistical analysis indicates that tillage practices are the primary factor influencing the Soil Quality Index (SQI). Among different treatments, soil quality indices exhibit the following order: NTSM>NTS>CTSM>CTS, with no-till demonstrating greater potential for soil quality improvement. Maize yields across treatments show no significant differences, while the variation in maize yields exhibits a significant positive correlation with the increase in SQI. Partially substituting chemical fertilizers with organic manure maintains maize yields while more effectively enhancing soil quality under no-till. These findings provide a scientific theoretical basis and technical support for enhancing soil fertility in the Northeast Black Soil Region.