Nowadays， engineering construction tends to offshore and deep-water areas. As a result， large diameter rock-socketed inclined （RSI） pile has been widely applied in structures foundation in port and dock areas due to its better ability to withstand horizontal loads. However， because of limited construction sites and designed piles parameters etc.， the RSI piles construction is usually carried out by percussion drilling， with its rate of penetration （ROP，0.1~0.3m/h） much lower than that of cast-in-place piles by other construction methods. Based on this， a force model of punch hammer was established in this paper， to study its forced state of dropping process when it is applied to drill a large diameter RSI pile. The influence laws of hammer weight， stroke， pile inclination， and friction coefficient between the punch and steel guard were studied by single-factor and two-factor analyses respectively. According to the analyses， it is found that the hammer weight and stroke are the key factors affecting the ROP of RSI piles when the pile inclination is constant， and the influence of friction coefficient can be ignored to a certain degree.