Using Langevin simulations, we numerically study the dynamics of two-dimensional colloids on a disordered substrate. With a decreasing strength of the interaction between colloids, we find a crossover from elastic to plastic depinnings, where a substantial increase in the depinning force is observed. Furthermore, we find a dynamical phase transition from the moving liquid to the moving smectic at high driving forces by decreasing the temperature. Peak effect occurs in the dynamical critical driving force across the transition, accompanied by a clear crossing of velocity-force dependence curves.