The invention belongs to the field of underwater detection and particularly relates to a method for locating identification and acoustic radiation prediction of an underwater complex-structure radiation noise source on the basis of a unit radiation approach. The method comprises the following steps of establishing a vibration sound transmission matrix, wherein a sound transmission modeling approach based on a unit radiation superposition approach is used, a radiation sound field of a piston on the surface of a regular baffle is adopted for simulating a radiation sound field of a piston on thesurface of an actual baffle, and a sound transmission matrix G of the surface of a target structure at a normal vibration velocity to the actual radiation sound field is obtained according to an analytical expression of the radiation sound field of the piston on the surface of the regular baffle; obtaining sound source distribution of the target structure, wherein a vibration sound transmission regularization matrix is adopted for solving an ill-posed problem of a noise source positioning recognition algorithm, an array is adopted for receiving data and a vibration sound transmission matrix ofvibration from the structural surface to a measurement matrix, and the vibration velocity distribution on the surface of a sound source of the target structure is obtained in combination with a Tikhonov regularization approach. The method overcomes the limitation of traditional point source spherical expansion sound transmission models and has higher accuracy and a wider application range.