The cluster topology management in the MANET network is studied in. The classic Lin-Gerla clustering algorithm is improved to increase the logical topological stability. By considering the node mobility in the communication systems, the notion of relative motion is introduced, and the nodes more stable are chosen as the cluster-heads, which effectively increases the stability of mobile network with Random Direction Model. Regarding the possible high concentration, a fast cluster splitting method is proposed for cluster maintenance. The simulation and performance analysis for the improved algorithm are given.