Three-dimensional distance measuring method and associated system

A three-dimensional distance measuring system, comprising:

• a light emitting device, for transmitting at least one beam set forming a projection plane directly onto a surface of an object, the beam set comprising a plurality of beams which are arranged in a linear arrangement and located on the projection plane and respectively transmitted according to a predetermined first path function to form detection points on the surface of the object;
• a focusing element, having a focus passed through by the beams of the beam set reflected by the surface of the object, wherein the focusing element, the beam set and the light emitting device are located on the same projection plane;
• a photosensitive memory element, for receiving the beams of the beam set passing through the focus of the focusing element to form a sense image;
• and
• a computation unit, electrically connected to the photosensitive memory element, for obtaining the sense image, obtaining a corresponding second path function according to an image formation position of each of the beams on the photosensitive memory element and a position of the focus of the focusing element, and calculating a sole intersection position of the first path function and the corresponding second path function of each of the beams.