The utility model discloses a float type magnetoelectric water level gauge. Relating to the technical field of hydrology and water resources, the device comprises a measuring tube, a stand column, floaters and a plurality of water level sensing rulers, the water level sensing ruler comprises a ruler body and a plurality of reed switches. The plurality of reed switches are fixedly arranged on the ruler body in a column array; wherein the plurality of ruler bodies are installed on the inner wall of the measuring tube, the installation distances of the plurality of ruler bodies along the axial direction of the measuring tube form an arithmetic progression, and the product of the tolerance values of the installation distances of the plurality of ruler bodies and the number of the ruler bodiesis equal to the distance between two adjacent reed switches on the same ruler body; wherein the stand column and the measuring tube are coaxially arranged, the floater is arranged on the stand columnin a sliding mode, a magnetic element is arranged on the floater, and the magnetic element is arranged on one radial face of the stand column. The water level gauge is high in environmental applicability, simple in structure, low in manufacturing cost, high in measurement precision, high in reliability and convenient to use and maintain.