The invention relates to the technical field of natural gas low temperature equipment, in particular to an LNG energy recovery process. By an LNG hydraulic turbine device (or expanding machinery in other forms), high pressure and low temperature LNG converts pressure energy to mechanical energy which is output by a supercharging end of the LNG hydraulic turbine device. Depressurized LNG is further cooled, a gas phase and a liquid phase generated in a depressurizing process are separated by a gas-liquid separation tank, the liquid LNG is charged to an LNG storage tank, and the gas phase BOG and BOG of the LNG storage tank are supercharged together by the supercharging end, namely, a BOG supercharger, of the LNG hydraulic turbine device. The LNG hydraulic turbine device replaces a J-T valve of the LNG product for expanding throttling, as the LNG is lower in temperature, output of the BOG is reduced, LNG yield is improved, and mechanical energy can be recovered by BOG supercharging of the BOG supercharging end.