Abstract: The invention discloses a positioning light beam emission system, a method and an indoor positioning system. A positioning space includes a plurality of positioning sub-spaces. A plurality of positioning light beam emission devices are fixed at predetermined positions in the plurality of positioning sub-spaces, respectively, and the positioning light beam emission devices are used to emit positioning light beams toward the respective positioning sub-spaces in a sweeping manner with a predetermined sweeping cycle and predetermined angular velocity. Each positioning light beam has a linear cross section and is rotated about a rotation axis in the sweeping manner, the rotation axis not perpendicular to an extended direction of the linear cross section.