The problem of determining the stress state of the rifled-bore barrel when firing was presented in this article. Where the effects of rifling parameters such as the quantity of grooves n, groove width a, depth of groove t, radius of groove corner ρ were investigated. A rifled-bore barrel has been modeled and investigated by using Ansys software on the basis of finite element method. The problem has only been treated under pressure load in static case. The article can be used for reference to improve the accuracy in calculating design and manufacturing gun barrel.