Abstract: In order to improve the anti-blast and protection design of offshore structures such as bridges and wharves, this paper proposes an efficient analytical method for calculating the circular cylindrical scattered wave pressure subjected to underwater explosion, aiming at the common cylindrical structures with constant cross-sections in offshore structures. Based on the theory of diffracted waves, this paper derives the time-domain solution of the scattered wave pressure of the cylindrical structure by the method of separation of variables in the cylindrical coordinate system according to the water body state equation and boundary conditions; The calculation accuracy of the scattered wave pressure time-domain solution proposed in this paper is verified by numerical simulation comparison. The numerical example shows that the calculation errors of the two methods are within the engineering allowable range. Based on the time-domain substructure analysis method that considers the compressibility of water, by comparing the analytical methods proposed in this paper without considering the compressibility of water, the influence of water compressibility on scattered wave pressure is analyzed.