This paper investigated the self-imaging properties of waveguides and its potential applications in laser power coherent combing. Based on phase propagation constant and mode propagation analysis method, the self-imaging formation process of waveguides was analyzed and simulated. The self-image lengths of several regular waveguides and corresponding requests were confirmed in detail. Its characteristics were also gathered up by the numbers. Two kinds of waveguides of square and equilateral triangle were used to simulate combining for multi-beams. The calculation results show applying self-imaging of waveguides to coherent combining will be propitious to exalt output power and keep high quality beam transmitting. It is a good approach to realize high power and high quality laser radiation.