The invention comprises a satellite-borne laser height measuring instrument footprint positioning method based on a passive target, solving the problem that echo signals of a flat terrain area are high in similarity by arranging an angle reflector array in the flat terrain area to mark the target echo to be measured in the flat terrain area, so that the high-precision positioning of the height measurement instrument footprint can be realized in a manner of waveform analysis in the flat terrain area, and the authenticity verification of the footprint position which is resolved by the height measurement instrument is finally realized. The method comprises angle reflector caliber design, angle reflector layout scheme, CCR energy contour line circle extraction, and footprint center extractionbased on a steepest descent method. The system includes a CCR caliber calculation module, a CCR layout scheme module and a CCR-based footprint positioning module. According to the technical scheme, the positioning of the height measurement instrument footprint can be achieved through the waveform analysis mode in the flat terrain area.