The Competitive Algorithm of Simulating Natural Tree Growth, a novel optimization algorithm, was applied to antenna design by calling the numerical electromagnetic simulation software based on Finite Element Method(FEM) to implement the automated antenna design, and then a novel microstrip plane tree-shaped antenna with end-fire characteristic was designed. This antenna maintained the end-fire radiation pattern with S11<-10 dB in the frequency band from 5.77 GHz to 5.93 GHz, and the end-fire gain is 5.4 dBi at the frequency of 5.8 GHz. According to the simulated result, a prototype of the antenna was fabricated and tested. Good accordance was obtained between simulated and measured results.