Aiming at the practical problem of ship waiting for tide at the tide riding water level，based on the hourly data of tide tables at stations of different tidal types in Chinese coastal area，we study the continuous navigable window period and waiting time of ship under the tide riding water level of 2 h with 90% assurance rate by using statistical method，analyze the reasons for the differences of navigation window period and waiting time when diurnal tide changes to semidiurnal tide from the perspective of water level duration curve，unequal daily high tide and annual change of mean sea level，and discuss the degree of influence of riding time and assurance rate on waiting time. The results show that the navigation window period decreases and the waiting time of ships tends to prolong from the diurnal tide to the semidiurnal tide. The influence of assurance rate on waiting time is more obviously.