A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid-accumulation effect, comprising a gravity-assisted heat pipe, a condenser, and a liquid tank, wherein the gravity-assisted heat pipe is disposed underground and the condenser and the liquid tank are disposed aboveground; the gravity-assisted heat pipe comprises an outer pipe and an inner pipe, a space between the outer pipe and the inner pipe is divided to form a ladder structure; the structure is characterized in that, a plurality of division plates and a plurality of liquid-level control tubes are provided in the space between the outer pipe and the inner pipe, wherein the plurality of division plates 10 are sequentially arranged in a vertical direction where the gravity-assisted heat pipe contacts a high-temperature rock and configured to divide the space between the outer pipe and the inner pipe into a plurality of sections, each two adjacent sections being communicated via one of the liquid-level control tubes, and the topmost section being communicated with a return pipe; the liquid-level control tubes are hollow pipes fixed in the division plates, wherein when a liquid level in one of the sections is higher than the tube, a liquid working medium flows to a lower section through the tube, so as to maintain the liquid level in the section below a certain level; the liquid working medium flows from the liquid tank through the return pipe into each of the sections of the space between the outer pipe and the inner pipe sequentially, absorbs heat from the high-temperature rock through a wall of the outer pipe, and vaporizes into a gaseous working medium; the gaseous working medium gets into the inner pipe and rises to the condenser; the condenser exchanges heat with environment to condense the gaseous working medium into the liquid working medium which is then transferred to the liquid tank; the liquid working medium in the liquid tank flows through the return pipe into the gravity-assisted heat pipe again to circulate; characterized in that a plurality of gas holes are provided on a surface of the inner pipe at an area between a top of each liquid-level control tube and the division plate above the liquid-level control tube, wherein after the liquid working medium absorbs heat and vaporizes into the gaseous working medium, the gaseous working medium gets into the inner pipe through the gas holes and rises to the condenser; openings are provided at a bottom of the inner pipe, wherein the liquid working medium in the bottommost section of the space between the outer pipe and the inner pipe flows into the inner pipe through the openings; an upper level detector and a lower level detector are provided on an inner wall at the bottom of the inner pipe, wherein the upper level detector is disposed below the gas holes of the bottommost section, and the lower level detector is disposed above the openings at the bottom of the inner pipe. the gravity-assisted heat pipe comprises an outer pipe and an inner pipe, a space between the outer pipe and the inner pipe is divided to form a ladder structure; the structure is characterized in that, a plurality of division plates and a plurality of liquid-level control tubes are provided in the space between the outer pipe and the inner pipe, wherein the plurality of division plates 10 are sequentially arranged in a vertical direction where the gravity-assisted heat pipe contacts a high-temperature rock and configured to divide the space between the outer pipe and the inner pipe into a plurality of sections, each two adjacent sections being communicated via one of the liquid-level control tubes, and the topmost section being communicated with a return pipe; the liquid-level control tubes are hollow pipes fixed in the division plates, wherein when a liquid level in one of the sections is higher than the tube, a liquid working medium flows to a lower section through the tube, so as to maintain the liquid level in the section below a certain level; the liquid working medium flows from the liquid tank through the return pipe into each of the sections of the space between the outer pipe and the inner pipe sequentially, absorbs heat from the high-temperature rock through a wall of the outer pipe, and vaporizes into a gaseous working medium; the gaseous working medium gets into the inner pipe and rises to the condenser; the condenser exchanges heat with environment to condense the gaseous working medium into the liquid working medium which is then transferred to the liquid tank; the liquid working medium in the liquid tank flows through the return pipe into the gravity-assisted heat pipe again to circulate; characterized in that a plurality of gas holes are provided on a surface of the inner pipe at an area between a top of each liquid-level control tube and the division plate above the liquid-level control tube, wherein after the liquid working medium absorbs heat and vaporizes into the gaseous working medium, the gaseous working medium gets into the inner pipe through the gas holes and rises to the condenser; openings are provided at a bottom of the inner pipe, wherein the liquid working medium in the bottommost section of the space between the outer pipe and the inner pipe flows into the inner pipe through the openings; an upper level detector and a lower level detector are provided on an inner wall at the bottom of the inner pipe, wherein the upper level detector is disposed below the gas holes of the bottommost section, and the lower level detector is disposed above the openings at the bottom of the inner pipe.