Provided is a horizontal height measurement method utilizing a non-prism total station. The method includes the steps of angle and distance asynchronous observation of a monitoring target, multi-point observation of the monitoring target and wave advanced observation, wave delay observation and continuous observation in a certain period. The angle and distance asynchronous observation of the monitoring target concretely includes the procedures that after the position of the water-level monitoring target is determined, a vertical angle is accurately measured, and at least two position numbers are obtained; the distance is measured by slightly moving a distance measurement target; the horizontal height data of the water level of a target position are calculated in real time. The multi-point observation of the monitoring target includes the procedures that multi-observation-point observation is carried out according to the angle and distance asynchronous observation method, and after coarse errors are calculated, detected and eliminated in real time, the average value of the multiple observation points is obtained, calculated and selected as the horizontal height of the water level of the monitoring target. The method solves the problems that distance measurement is affected or can not be carried out due to dampness of reflecting surfaces of water side media is solved, avoids man-made collimating errors of the target water level or the errors due to the fact that reflective medium surfaces are irregular and can not be collimated easily, avoids influences of large waves at turbulent rivers and treacherous shoals, and greatly improves benefits.