Shear strain is exactly described by combining the piezoelectric constitutive equations of $d_{{\rm 15}}$ mode with the Timoshenko beam model. We provide an electromechanical model to evaluate the energy harvesting performance of shear mode cantilevered piezoelectric bimorph in series connection. The output peak voltage–frequency and the output peak power–frequency curves are simulated by using the proposed model at different load resistances. The results are in good agreement with the finite element simulation results, indicating that the proposed model is valid for evaluating the energy harvesting performances of the cantilevered piezoelectric bimorph. The variations of the output peak voltage and power with load resistance change for excitation are also discussed. Moreover, the effect of proof mass on the energy harvesting performance is analyzed at certain load resistance. The proposed model can be used for the structure optimized design and performance improvement of shear mode piezoelectric energy harvesting.