Based on a coupled map lattice model, we present an approach of unilateral coupling to implement the synchronization of spatiotemporal chaos. Our numerical simulations show that the two spatiotemporal systems can accurately become synchronized by appropriately selecting the coupling strength and the equilibrium coefficient. We calculate the largest conditional Lyapunov exponent，so as to give the minimum coupling strength that can achieve the synchronization，and the functional relationship between the minimum coupling strength and the system parameters. The simulation results also indicate that this method is robust against noise.