Method, apparatus, and system for measuring load of crane and crane

A method, apparatus (20), and system for measuring a load of a crane, and the crane. The method comprises: step A: measuring the tensions of tension units evenly arranged on both sides of a boom, thereby acquiring two tension values; and step B: determining, on the basis of the two tension values, if a side load of the crane exceeds a predetermined range, then outputting the determination result. The method, apparatus (20), and system are capable of measuring conveniently and accurately the side load of the crane. Combined with the prior apparatus, only two tension measuring apparatus (31 and 32) are required to be added, increase in costs is minimal. In addition, when the two tension measuring apparatus (31 and 32) are added, convenience is allowed in determining if the load of the crane is overloaded, more direct and accurate when compared with the load measuring method for the prior torque limiter. The problem in measuring the side load of the crane is solved.