Abstract: Level gauging for pressure vessel is a task which is not perfectly brought to success until the presence of radar level gauge, the promising device in other industrial fields as well. This paper describes the working principle and structure of the radar device, analyzes the problem met with in its application and solutions to them. It is believed that.without welding and interruption of operation, radar level gauge can be installed on LPG or C₃ tank. A well developed installing techniques proved by multiple fields test are introduced, calibration, metering error and differential temperature of the device installed on the outside of the tank are discassed and corresponding sollution are given.