A numerical model is established for the performance of thermocompressor with gap regenerator and orifice-reservoir. There exists the maximum output acoustic power with an optimal orifice opening. High pressure and heating temperature raise the acoustic power of the system. Acoustic power is measured during experiment to validate the numerical results. The trends of numerical results accord with the experimental one. Analysis shows that large clearance volume ratio and heat transfer insufficiency of regenerator should be responsible for the difference.