The catalytic pyrolysis of heavy gas oil derived from Canadian synthetic crude oil on zeolite catalyst was conducted in a confined fluidized bed reactor. The optimal reaction temperature, weight hourly space velocity, steam-to-oil weight ratio, and catalyst-to-oil weight ratio were 660 degrees C, 9.5 h(-1), 0.6, and 20, respectively. The yield of total light olefins was 36.4 wt % under these optimal conditions. The overall reactants and products were classified into seven species, and a seven-lump kinetic model with 15 rate constants and a catalyst deactivation constant was proposed. Kinetic constants at 620, 640, 660, and 680 degrees C were estimated by a nonlinear least-squares regression method. Preexponential factors and apparent activation energies were then calculated according to the Arrhenius equation. The feed lump had larger rate constants and smaller apparent activation energies than did the intermediate product lumps. The seven-lump kinetic model showed high calculation precision and the predicted yields agreed well with the experimental values.