The invention provides an unattended operation LNG dispenser which comprises a filling gun, a gas pipeline, a control module, a POS machine, a mass flow meter and an emergency shut-off valve. The gaspipeline is in communication with the filling gun; the POS machine is electrically connected to the control module, and the POS machine pre-authorizes a bank card and transmits an authorization signalto the control module; the mass flow meter is used for detecting the mass of LNG injected into a vehicle-mounted tank and transmitting a detected mass signal to the control module; the emergency cut-off valve is used for opening or closing the gas pipeline, and the control module controls the emergency cut-off valve based on the authorization signal to perform gas filling; and after gas filling is stopped, the control module generates a fee signal based on the mass signal and transmits the fee signal to the POS machine to complete fee deduction. According to the unattended operation LNG dispenser, a driver can achieve self-help LNG filling, a filling person and a cashier are not needed in a natural gas station, while safe operation is ensured, the filling efficiency is improved, and the construction cost of the natural gas station is reduced.