By modeling and calculating the piezoelectric ceramic patches of cantilever generators,the effects of different positions of the piezoelectoic patches on the generation ability of the generators were analyzed and the optimum positions of the piezoelectric ceramic patches under the first and second vibration modes were obtained with Euler-Bernoulli model and by testing the open circuit voltages, short-circuit currents of generators and the performance of LED lighting. Experiments indicate that the generators show the optimum performance under the first vibration mode when the piezoelectric ceramic patches locate at the root of the cantilever. Its opening voltage and short current are 4 times and LED power is 10 times of experimental data of other three generators. Moreover,the generation ability is investigated under the second vibration mode. When the ceramic patch respectively locates at the middle and the root of cantilever, the generation ability of the former is superior to that of the latter,and the opening voltage and short current of the former are 1.2 and 1.9 times those of latters respectively through six generator experiments. In addition, LED power of the former is 1.4 times those of the others.It points out that the piezoelectric ceramic patches should be located at the root of beam under the first vibration mode and at the middle of beam under the second mode to improve the generation efficiency.