Abstract: The ignition process and combustion process in bore of coated-propellant charge with low temperature sensitivity were analyzed. The two-phase fluid model of the complicated charge structure which contains main charge,coated-propellant charge,tail tube propellant, combustible case and central spread tube was established,and a computer program was written.As an example,a computation of a lined gun was carried out. The results show that the calculated values conform to the experimental values.