The purpose of this paper is to find the invariant solutions of the reduction of the Navier-Stokes equations where s=z/y ((U_yy(t,s,y)－U_t(t,s,y))y－2sU_sy(t,s,y))y＋（s²＋1)U_ss(t,s,y)＋2sU_s=0 This equation is constructed from the Navier-Stokes equations rising to a partially invariant solutions of the Navier-Stokes equations. Group classification of the admitted Lie algebras of this equation is obtained. Two-dimensional optimal system is constructed from classification of their subalgebras. All invariant solutions corresponding to these subalgebras are presented.