In view of the secret demand of communication network for unmanned aerial vehicle (UAV) in penetrating reconnaissance mission under the complex battlefield environment, considering the limited energy carried by nodes and the unbalanced of energy consumption during the data transmission, a clustering optimization algorithm for UAV formation based on ultraviolet communication is proposed in this paper. First, on the basis of establishing the wireless ultraviolet communication link model and energy consumption of nodes, the selection of cluster heads and inter-cluster communication process of low energy adaptive clustering hierarchy (LEACH) algorithm is improved. Then, the weight functions of node residual energy and link reliability are introduced to select cluster heads, and the topology optimization between cluster heads is carried out by generating optimally rigid graph. The simulation results show that the algorithm improves the connectivity between clusters and delays the phenomenon of node death in the network. Compared with the LEACH algorithm, the time for the first occurrence of dead nodes and half of dead nodes in the network is delayed by 25.2% and 21.4%, respectively. The connectivity and energy balance of the network are improved.