Fire water monitor plays an important role in the fire fighting. A liqumatic fire water monitor with self-swing device was designed, the working principle and its components were also expounded in detail. The internal flow performance was simulated using fluent software, the influence rules on outlet velocity were analyzed by changing different angles of the monitor head and diameters of the monitor body. At the same time, the experimental tests were also carried out on the test rig. The simulation results accorded with the theory calculations in general. So, the rationality and accuracy of the designed fire water monitor was verified, and the relevant results can also provide a certain theoretical references for the design of other types of fire water monitor.