In order to study the ignition operating characteristics of the pasty propellant rocket engine, the burning surface change model of pasty propellant was built, and regression equations of pasty propellant were deduced in each stage. The calculating procedure was programmed and the transient pressure of combustion chamber under different transport pipeline diameter and pasty propellant initial accumulation was calculated. Also, the ignition tests were carried out successfully based on a pasty propellant rocket launch test system, and the ignition characteristics of the rocket engine in each working stage were analyzed. Results show that the data calculated by the procedure are in good agreement with the experimental and the maximum absolute error are 5.7%. When the pasty propellant initial accumulation doubled, the initial pressure peak increases by 42.8%. Under the same condition, as the diameter of the pipeline decreases by 60%, the initial combustion time and residual combustion time decrease by an average of 66.5% and 26.1%. The initial pressure peak can be decreased and stable burning time can be increased by reducing the initial packing quantity of pasty propellant, in addition, the stable burning time can be increased apparently by reducing the diameter of transport pipeline.