Combustion chamber pressure is one of the important indicators reflecting the comprehensive performance and overall level of liquid rocket engines, which directly affects the working parameters of engine systems and components. This article conducts theoretical analysis and research on the combustion chamber pressure of a high-pressure staged combustion LOX/Kerosene rocket engine. Based on the balance equation as the theoretical foundation, combined with the static characteristic models of various components of the engine, a simulation calculation model for the static parameters of the engine system is constructed. Use this model to calculate the theoretical limit chamber pressure of a high-pressure staged combustion LOX/Kerosene rocket engine, and analyze the factors affecting the selection of chamber pressure in combination with two types of high-pressure staged combustion l LOX/Kerosene rocket engines. The calculation results indicate that an increase of 10% in chamber pressure requires an increase of approximately 8% in pump component efficiency, an increase of approximately 55 K in turbine inlet temperature, or an increase of approximately 0.2 in turbine pressure ratio, resulting in a reduction of approximately 5% in thrust chamber throat diameter and an increase of approximately 10% in gas side heat flux. In actual work development, the chamber pressure should be selected within a certain range. If it is too high, it will affect reliability and reusability, etc. If it is too low, it will affect performance, component matching, etc.