The invention discloses a splashing preventing device of a liquefied natural gas (LNG) filling machine. The splashing preventing device comprises a measuring and control system, an LNG inlet, an LNG filling gun, an LNG returning port and a pressure release valve, wherein the LNG inlet is connected with an LNG feeding branch through a flange; a mass flow meter, a pressure sensor and a second electric valve are sequentially arranged on a pipeline of the LNG feeding branch; the second electric valve is connected with the LNG filling gun through an LNG filling hose; a pressure release branch is arranged between the second electric valve and the LNG filling hose; the pressure release valve which is connected with a first one-way valve is arranged on the pressure release branch; the one-way valve is connected with the LNG returning port through a flange; the mass flow meter, the pressure sensor, the second electric valve and the pressure release valve are connected with the measuring and control system. According to the splashing preventing device of the LNG filling machine, the pressure release branch is arranged at the downstream of the LNG feeding branch and connected with the LNG returning port through the pressure release valve; the measuring and control system can control the on and off of the pressure release valve, so as to achieve the pressure release of the LNG feeding pipeline, and as a result, the problem that the filling gun is difficultly drawn out after the filling is finished can be overcome; the LNG can be prevented from splashing, and thus the safety can be improved.