The invention discloses a heat pipe air conditioner with an adjustable filling rate. The heat pipe air conditioner comprises a compressor, a condenser, a refrigerant filling rate adjustment device, a throttling device and an evaporator. A gas-liquid separator is arranged between the compressor and the evaporator. An oil separator is arranged behind the compressor. A one-way valve is arranged on a compressor branch. A heat pipe branch is connected in parallel with an outlet of the evaporator and an outlet of the one-way valve. A first one-way solenoid valve is arranged on the heat pipe branch. A drying filter is arranged in front of the throttling device. A liquid separator is arranged behind the throttling device. A second one-way solenoid valve is connected in parallel with an inlet of the drying filter and an inlet of the liquid separator. The refrigerant filling rate adjustment device is arranged between the condenser and the drying filter. In the heat pipe air conditioner, the filling rate is adjusted by the refrigerant filling rate adjustment device, so the whole system runs at optimal filling rates in a compression cycle refrigeration mode and a heat pipe cycle refrigeration mode respectively, efficiency is improved and good energy-saving effects are achieved.