Abstract: Due to the influence of fiber winding molding process and the variable curvature/thickness of the dome, the stress state of the dome of the composite pressure vessel was relatively complicated. It was of great significance to accurately predict the thickness of the winding layer of the dome, which was of great significance for constructing a high-precision finite element model and guiding engineering applications. In order to solve the above problems, this study developed a layer-by-layer prediction method for the winding layer thickness of composite pressure vessel dome based on the dual formula method and cubic spline function method. The effects of polar hole radius, the thickness of single-layer yarn thickness and number of winding layers on the thickness and winding angle of the dome were studied. The results show that as the polar hole radius increases, the thickness of the single-layer yarn sheet in the dome decreases gradually, the extreme value of the fiber winding layer of the dome gradually decreases, and the variation of winding angle at the equatorial circle decreases with the decrease of the radius of the polar hole and the thickness of single-layer yarn. Furthermore, by comparing the thickness of each layer of the dome, it is found that the thickness of each winding layer from the inner layer to the outer increases first, then decreases, and finally tends to be the same as the radius of parallel circle increases.