Double diffusive convection along a heated inclined wall in a pre-existing stratified solutal gradient is investigated numerically. The numerical simulations are carried out in a tank with one wall inclined at 45 degrees. The fluid motion is initiated by abruptly varying temperature of the inclined sildwall. The governing parameter which characterizes the patterns of fluid motion is the effective Rayleigh number, according to which three kinds of flow patterns are observed. In subcritical regime, weak cells are generated successively near the top and bottom walls. In this regime, the cells near the bottom wall march slowly to the upward region of the tank, once in a while, the cells near the top march to the downward region. In transitional regime, more rapid and extensively successive growth of cells along the heated inclined sidewall is observed. In supercritical regime, the cells appear simultaneously along the heated inclined sidewall.