The invention discloses a method for improving the performance of a differential steering system of tracked vehicle hydraulic machinery, aiming at multiple optimal parameters such as planet row characteristic parameters, hydraulic closed loop system parameters, motor post-transmission ratio, dead axle gear transmission ratio and the like of the differential steering system of hydraulic machinery, multiple evaluation sub-objects such as the steering dynamic property (dynamic factor), the steering flexibility (steering radius), the steering rapidity (steering time) and the like of the tracked vehicle are evaluated comprehensively; the mutual coupling relationships between the optimal parameters are processed by using a layer partitioning problem space method, so that each optimal parameter is enabled to correspond to one layer problem space, thereby the flexibility of optimal parameter selection is increased, the analysis calculation on an ineffective parameter combined scheme during the optimization process is avoided, and the parameter optimization efficiency is improved.