Positioning method and device for crane

The invention discloses a positioning method for a crane. The positioning method comprises the following steps of providing at least one light receiving device on the bottom surface of a trolley frame, and respectively providing at least one camera on the two sides of each light receiving device; respectively providing at least one laser generator on the two sides of a ground weight, wherein the relative position relationship between each laser generator and the weight corresponds to the relative position relationship between the corresponding light receiving device and a lifting appliance ofthe crane; enabling the laser generators to emit laser to the light receiving devices above; and observing laser spots received by the light receiving devices by an operator through the cameras so asto judge the relative position relationship between the lifting appliance of the crane and the weight. The invention further provides a positioning device for the crane. According to the positioning method and device disclosed