The stability of Couette-Poiseuille flow of the mixture of collisionless dispersed big particles with liquid is considered. It is shown that there is additional mechanism of influence of velocity profile shape on the stability characteristics when dispersed particles of definite radius are presented in the stream. Hereat the appreciable stabilization of velocity profile for definite ranges of parameters, characterizing flow, is observed. Generally profile deformation causes the lost of symmetry of the first unstable mode of perturbations and the predominance of viscous dissipation anear walls over instability generation.