【Objective】This study aimed to illustrate the impacts of different tillage practices on chitin degrading microbial communities and chitinase activity in farmland black soil, and to explore the main environmental factors in driving a change in chitin degrading microbial communities and chitinase activity. 【Method】Based on the long-term positioning platform of different tillage practices in black soil and the combination of fluorescence quantification and high throughput sequencing technology, this research intends to study the effects of long-term different tillage practices (Conventional tillage, No-tillage, Sub-soiling tillage, Moldboard plowing tillage) on chitin degrading bacteria harboring chiA gene abundance, microbial communities and chitinase activity in 0~40 cm soil layers. 【Result】Results showed that no-tillage increased chiA gene abundance in the 0~20 cm soil layer. Lower chiA gene abundance, alpha diversity and proteobacteria relative abundance, and higher actinobacteria relative abundance in the 20~40 cm soil layer of no-tillage than other tillage practices. The abundance of chiA gene and microbial community structure was significantly affected by soil pH, mean weight diameter and nutrients. Compared with conventional tillage, the chitinase activity increased in 0~20 cm soil layer under no-tillage, and the chitinase activity was enhanced in 0~40 cm soil layer under sub-soiling tillage and moldboard plowing tillage. The simulation result of the structural equation modeling showed that chitinase activity was directly affected by the tillage practice, soil depth, mean weight diameter, organic carbon, total nitrogen, total phosphorus, chiA gene abundance, and actinobacteria relative abundance. 【Conclusion】These results provide a theoretical basis for understanding the effect of different tillage practices on soil chitin degradation in black soil areas.