In the ocean, due to the non-ideal channel environment, it is difficult to locate the position of the vessel in the sea quickly and exactly. In order to improve the location accuracy of accident vessel in the ocean, one method is to analyze the main cause of the different kinds of the measurement errors to find their solutions to decrease the errors. The subject that Kalman filtering technology is applied in wireless location system is researched in this paper, which can reduce the measurement error and greatly improve the location accuracy.