Monolithic pump is an important technology in the modern automotive industry for clean combustion.It consists of piston pump highpressure tubing and injectors.Piston pump is a single pump hydraulic parts.Its structure is compact,and it has high working pressure and can maintain high efficiency,so it is very important to analyze the effect of the length of high pressure tubing on its strength.Finite element model was preprocessed by finite element software ICEM CFD.The fluid distribution in the process of pumping oil was obtained by CFX analysis and calculation of the fluid field matching with different highpressure tubing lengths.ANSYS software was used for static analysis of different programs to get the stress distribution of each program and to meet the structural strength of the optimal highpressure tubing length.According to the analysis of this coupling method,it can provide guidance and reference for the design and optimization of the piston pump.