Needle selection mechanism of flat knitting machine and flat knitting machine

The invention discloses a needle selection mechanism of a flat knitting machine and the flat knitting machine, belongs to the field of flat knitting machines, solves the problem that the existing flat knitting machine can only perform direct selection knitting or pre-selection knitting, and adopts the technical scheme that the needle selection mechanism of the flat knitting machine comprises a triangular bottom plate, and a needle selector is arranged on the triangular bottom plate; the knitting needle assembly comprises a knitting needle, an auxiliary stitch and a stitch selecting stitch, a knitting route and a tucking route are arranged on the triangular bottom plate, the triangular bottom plate is connected with a direct selection return guide block and a pre-selection return guide block, the direct selection return guide block is provided with an avoiding position and a working position, the direct selection return guide block is located on the outer side of the needle selector, and the pre-selection retu