Abstract: The paper studied the prediction method of ship bottom slamming pressure based on the randomness of ocean wave surface.The effect of longitudinal angle between keel and wave surface on slamming pressure was analyzed and the quantitative relationship was established.The factors of ship motion and inclination angle of wave were considered by introducing wave surface condition while calculating slamming pressure of ship bottom.MonteCarlo simulation method was used to study the statistics characters of slamming pressure with the same relative velocity between ship sections and wave surface.The results show that the method of ship bottom slamming pressure calculation considering the longitudinal angle can properly reflect the influences of factors in terms of wave surface condition and bottom wave surface.This study provides the foundation for a further study of extreme value of slamming pressure at short-term sea state.