Abstract
Sai Gon - Vung Tau channel is the most important channel of the country. For the safe of navigation, the risk of collision between ships should be early determinded and informed to the mariners. Due to the channel’s conditions, the ship’s course, speed are changed varriously. The evaluation of the risk of collision based on Rule 7 of Colreg72 is not suitable for this channel. Another method for detection the risk of collision should be found.