An optical signal transmission structure of a laser distance measuring device, comprising: a laser pipe, suspended statically and directly above a center of a rotation disk, to emit a laser beam; a light projector module to project the laser beam of said laser pipe onto a target; a lens, disposed on said rotation disk, to receive the laser beam reflected from said target; and a circuit board, disposed statically in a position opposite to that of said rotation disk, wherein the laser beam received by said lens is irradiated onto a light sensor element on said circuit board, to produce at least one photoelectric signal, so that circuits on said circuit board can determine a distance to said target based on said at least one photoelectric signal, characterized in that a plurality of calibration marks forming a dark-and-bright alternation are provided on an outer side of said rotation disk, wherein the laser distance measuring device further includes an outer shell and a turning angle detector on the outer shell, wherein the turning angle detector is configured to sense variations of the dark-and-bright alternation to determine a turning angle of the rotation disk based on said dark-and-bright alternation, and in that said light projector module further includes a first reflection plate and at least one second reflection plate (164a, 164b), wherein said first reflection plate is provided on said rotation disk right below said laser pipe, said first reflection plate forms an angle of 45 degrees with a horizontal plane to reflect the laser beam of said laser pipe to said at least one second reflection plate (164a, 164b), then said at least one second reflection plate (164a, 164b) reflects the laser beam to said target, and in that said light projector module further includes a third reflection plate, disposed at a back side of said first reflection plate, such that the laser beam reflected by said target is transmitted onto said third reflection plate through said lens, then it is reflected by said third reflection plate downward to said light sensor element on said circuit board, and said third reflection plate and said first reflection plate are of a same plate, thus they are made into double-face reflection plate after special processing; or said third reflection plate and said first reflection plate are glued back-to-back into two different plates. a laser pipe, suspended statically and directly above a center of a rotation disk, to emit a laser beam; a light projector module to project the laser beam of said laser pipe onto a target; a lens, disposed on said rotation disk, to receive the laser beam reflected from said target; and a circuit board, disposed statically in a position opposite to that of said rotation disk, wherein the laser beam received by said lens is irradiated onto a light sensor element on said circuit board, to produce at least one photoelectric signal, so that circuits on said circuit board can determine a distance to said target based on said at least one photoelectric signal, a plurality of calibration marks forming a dark-and-bright alternation are provided on an outer side of said rotation disk, wherein the laser distance measuring device further includes an outer shell and a turning angle detector on the outer shell, wherein the turning angle detector is configured to sense variations of the dark-and-bright alternation to determine a turning angle of the rotation disk based on said dark-and-bright alternation, and in that said light projector module further includes a first reflection plate and at least one second reflection plate (164a, 164b), wherein said first reflection plate is provided on said rotation disk right below said laser pipe, said first reflection plate forms an angle of 45 degrees with a horizontal plane to reflect the laser beam of said laser pipe to said at least one second reflection plate (164a, 164b), then said at least one second reflection plate (164a, 164b) reflects the laser beam to said target, and in that said light projector module further includes a third reflection plate, disposed at a back side of said first reflection plate, such that the laser beam reflected by said target is transmitted onto said third reflection plate through said lens, then it is reflected by said third reflection plate downward to said light sensor element on said circuit board, and said third reflection plate and said first reflection plate are of a same plate, thus they are made into double-face reflection plate after special processing; or said third reflection plate and said first reflection plate are glued back-to-back into two different plates.