Disclosed is a detection process for a hole group of a parallelogram web member. A standard beam head mold can be adopted for solving the measuring problem. The standard beam head is a solid measuring mold produced through simulation of a structural size of a diagonal web member end, a connecting state of a bridge diagonal with a chord member is simulated, the standard beam head and a terminal plate of a finished web member or a chord member are positioned and bolted through a splice plate in a theoretical size and a certain amount of punching nails and high-strength bolts, after the assembly, and the contact ratio of bolt holes are detected to determine whether the hole group of the member pieces are qualified according to manufacturing specification requirements for railways and steel bridges. The process is high in precision and working efficiency, strong in operability and suitable for hole group detection of the parallelogram web member in cable-stayed bridge steel beam erection construction in which a whole node box type is adopted for an upper chord member and a lower chord member.