As the core component of common rail system of diesel engine,the robustness of injector system is an important guarantee of precise injection technology.Aiming at the stability analysis of the injector system and the difficulty of multi parameter matching and setting,the Monte Carlo method Latin hypercube sampling principle was used to calculate the correlation of the structural parameters.The results show that the correlation between the pre injection amount and the damping hole diameter A ,damping hole diameter B ,spring preload and valve core diameter is high,and the diameters A and B have a great impact on the main injection process.The NLPQL algorithm was used to optimize the key structural parameters of the system,the pre injection and main injection flow of the injector are increased by 10.7% and 18.3% respectively,the pre injection and main injection capacity are increased by 8.2% and 25.6% respectively,and the pre injection and main injection closing are shortened by 6.8% and 15.9% respectively,which effectively improves the robustness of the common rail injection system and the fast and accurate injection technology.