•The impact of the preceding layer stacking on rear filament winding is considered.•An improved cubic spline function approach and a novel parabola method were proposed.•The strength analysis of gas cylinders based on the parabola method was carried out.•The parabola method adapts well to cylinders with varied sizes and ply schemes. Due to the characteristics of changing angle and thickness, predicting the outer contour of the vessel dome has been a challenging task in composite pressure vessel design. The impact of preceding layer fiber stacking on subsequent filament winding has never been considered in existing methods of dome thickness calculation. So we developed an improved cubic spline function approach and a novel parabola method that takes preceding layer fiber stacking into account. The example findings show that the improved cubic spline function approach has a weakness in that the selection of several critical parameters is not clearly described and heavily reliant on actual engineering knowledge. The parabola approach described in our study is not only simple in design, but also adapts well to dome contour of gas cylinders with varied sizes and ply schemes. Moreover, the strength analysis of composite gas cylinders was carried out by finite element method. The results show high consistency with hydraulic burst test results, which clearly demonstrates that the parabola method we proposed can effectively realize the precise modeling of composite pressure vessels and will be very beneficial in the design of composite pressure vessels.