The present invention discloses a method and system for implementing a three-dimension positioning. The method comprises: receiving, by an optical sensor, infrared rays emitted from an infrared reference light source; and determining a position of the optical sensor with respect to the infrared reference light source based on attributes of the infrared reference light source in images obtained by the optical sensor, so as to implement a three-dimension relative positioning of the optical sensor. The method and system determine the position of the optical sensor with respect to the infrared reference light source by means of the attributes of the infrared reference light source in the images, which are simple in implementation, of a relatively low cost and can provide an excellent positioning function for application contexts of relative positioning (such as immersive video), which greatly improves the experience of a user.