The synchronization of two symmetrical and nonsymmetrical nonlinear-coupled chaotic systems is discussed. A special nonlinear-coupling term is constructed by suitable separation between linear and nonlinear terms of the chaotic system, and the phenomenon of stable chaotic synchronization can be found in a certain region of the coupling strength. We used this method in hyperchaotic synchronization of Rssler system. The method can also be generalized to a form for hyperchaotic synchronization of networks linked by star coupling connection. By varying parameters in a region, we observed its effects on the stability of chaotic synchronization. Numerical calculation showned that the method is effective for hyperchaotic synchronization of Rssler system.