In the paper, a novel traffic flow model is proposed to describe the behavior of vehicles moving on a curved road with a slope. We investigate the related influences on uniform traffic jam analytically and numerically. Based on control theory, the condition for no traffic jam is obtained analytically. Finally, simulations are carried out to verify the new traffic flow model. The theoretical and numerical results show that the related factors including the friction coefficient, radius of curvature, slope of the curved road and the parameter λ have major effects on the stability of traffic flow respectively.