The invention relates to the beam combining field of a multi-single-tube semiconductor laser, in particular to a multi-single-tube semiconductor laser collimating beam combining structure which facilitates heat dissipation and beam close arrangement, comprising a plurality of sets of collimating beam combining units arranged on a planar bottom plate for wavelength beam combining or polarization beam combining. A plurality of collimated beam combining units in each group perform spatial beam combining. Each collimating beam unit includes a beveled heat sink, a laser chip assembly (COS), a fastaxis collimating lens (FAC), a slow axis collimating lens (SAC), and a 45 degree mirror. By reasonably designing the angle of the inclined heat sink, slow axis collimator lens (SAC) and 45 degree mirror, the slow axis direction of the output beam of the collimating beam combining unit can be parallel to the mounting surface of the planar bottom plate, and the output beam of a group of collimatingbeam combining units can be parallel to each other and the beam spots can be arranged closely in the direction of the fast axis without spacing. The structure of the invention does not need steps, hasgood cooling uniformity and heat dissipation efficiency, closely arranges light beams, and has high coupling efficiency.