According to electro-mechanical equivalent principle, piezoelectric tube stack electro-mechanical equivalent circuit is derived by the admittance of single piezoelectric thin tube. The resonance frequency of piezoelectric tube stack for radial vibration mode is also calculated. The relationship between resonance frequencies and average radius, thickness and height with radial vibration mode are obtained through analytical calculation. And radial vibration mode is simulated by FEM .Analytical calculation and FEM simulation results are compared. They coincide well with each other.