The invention relates to an existing railway survey method based on a total station. In the method, the total station and an electromagnetic wave reflection device are adopted to survey an existing railway. The survey method comprises the following steps: firstly arranging the electromagnetic wave reflection device at the center of the existing railway line to be surveyed by virtue of a traditional measuring square ruler; determining position of the total station, and surveying the line center by the electromagnetic wave reflection device to obtain distance (slant distance), horizontal angle and vertical angle of the surveyed line and 3D coordinates of survey points (X, Y and H) of the measured line (slope distance); and then analyzing and calculating the survey data by a PDA, and performing survey on line mileage, center line, traverse, elevation and other railway equipment. The existing railway survey method based on a total station reduces on-track operation times of operators, guarantees safety of surveyors, instruments and equipment, accuracy and reliability of the surveyed data, improves production efficiency of the existing railways, and alleviates labor intensity of the operators.