A level sensor system, for use in remote monitoring the liquid level in a tank, wherein, the sensor system comprises: a first fixed portion installed at the opening of the tank, a guide tube inserted into the tank below the first fixed portion, the guide tube is provided with a plurality of ports (27, 28) to allow the liquid level in the guide tube to be equal with the liquid level in the tank; as well as a second fixed portion, attached to the first fixed portion and located on the upper side of the first fixed portion; a first level response unit, comprising: a float inside the guide tube floating on the surface of the liquid, that moves up and down as the liquid level varies in the guide tube; a rotating shaft (19, 19'), said rotating shaft mechanically and coaxially coupled with the float, the rotating shaft being configured to rotate around a fixed axis of rotation when the float moves up and down; a second level response element, including a PCB attached to the second fixed portion; characterized by further comprising: a permanent magnet, mounted on the upper end of the rotating shaft on the axis of rotation, for rotating together with the rotating shaft; the second level response element, further including a magnetoresistive angle sensor chip attached to the PCB on the side towards the permanent magnet, and the magnetoresistive angle sensor chip is electrically interconnected with a control circuit (161, 162, 163); and the magnetoresistive angle sensor chip is configured to output an analog voltage signal to the control circuit in correspondence with the angle of rotation of the permanent magnet, and the control circuit is configured to calculate the height of the liquid level according to the analog voltage signal. a first fixed portion installed at the opening of the tank, a guide tube inserted into the tank below the first fixed portion, the guide tube is provided with a plurality of ports (27, 28) to allow the liquid level in the guide tube to be equal with the liquid level in the tank; as well as a second fixed portion, attached to the first fixed portion and located on the upper side of the first fixed portion; a first level response unit, comprising: a float inside the guide tube floating on the surface of the liquid, that moves up and down as the liquid level varies in the guide tube; a rotating shaft (19, 19'), said rotating shaft mechanically and coaxially coupled with the float, the rotating shaft being configured to rotate around a fixed axis of rotation when the float moves up and down; a second level response element, including a PCB attached to the second fixed portion; characterized by further comprising: a permanent magnet, mounted on the upper end of the rotating shaft on the axis of rotation, for rotating together with the rotating shaft; the second level response element, further including a magnetoresistive angle sensor chip attached to the PCB on the side towards the permanent magnet, and the magnetoresistive angle sensor chip is electrically interconnected with a control circuit (161, 162, 163); and the magnetoresistive angle sensor chip is configured to output an analog voltage signal to the control circuit in correspondence with the angle of rotation of the permanent magnet, and the control circuit is configured to calculate the height of the liquid level according to the analog voltage signal. a float inside the guide tube floating on the surface of the liquid, that moves up and down as the liquid level varies in the guide tube; a rotating shaft (19, 19'), said rotating shaft mechanically and coaxially coupled with the float, the rotating shaft being configured to rotate around a fixed axis of rotation when the float moves up and down; a second level response element, including a PCB attached to the second fixed portion; characterized by further comprising: a permanent magnet, mounted on the upper end of the rotating shaft on the axis of rotation, for rotating together with the rotating shaft; the second level response element, further including a magnetoresistive angle sensor chip attached to the PCB on the side towards the permanent magnet, and the magnetoresistive angle sensor chip is electrically interconnected with a control circuit (161, 162, 163); and the magnetoresistive angle sensor chip is configured to output an analog voltage signal to the control circuit in correspondence with the angle of rotation of the permanent magnet, and the control circuit is configured to calculate the height of the liquid level according to the analog voltage signal. a permanent magnet, mounted on the upper end of the rotating shaft on the axis of rotation, for rotating together with the rotating shaft; the second level response element, further including a magnetoresistive angle sensor chip attached to the PCB on the side towards the permanent magnet, and the magnetoresistive angle sensor chip is electrically interconnected with a control circuit (161, 162, 163); and the magnetoresistive angle sensor chip is configured to output an analog voltage signal to the control circuit in correspondence with the angle of rotation of the permanent magnet, and the control circuit is configured to calculate the height of the liquid level according to the analog voltage signal.