With the aim to enhance the energy conversion efficiency of the rainbow shape piezoelectric transducer, an analysis model of energy conversion efficiency is established based on the elastic mechanics theory and piezoelectricity theory. It can be found that the energy conversion efficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and ma- terial properties from the analysis model. Simulation results show that there is an optimal length ratio to generate maximum en- ergy conversion efficiency and the optimal length ratios and energy conversion efficiencies of beryllium bronze substrate trans- ducer and steel substrate transducer are （0.65, 2.21%） and （0.65, 1.64%） respectively. The optimal thickness ratios and energy conversion efficieneies of beryllium bronze substrate transducer and steel substrate transducer are （1.16, 2.56%） and （1.49, 1.57%） respectively. With the increase of width ratio and initial curvature radius, both the energy conversion efficiencies de- crease. Moreover, beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.
