An L/C constant admittance switch model has the advantages of a constant admittance matrix and high real-time simulation efficiency. This is one of the main switch models in electromagnetic transient simulation. However, virtual power loss significantly affects the simulation accuracy. To eliminate the virtual power loss, a L/C constant admittance switch model based on pole-zero matching technique is proposed. First, the switch structure is selected according to the Z-transform pole distribution law on the basis of stability. Then, the switch model is discretized with a pole-zero matching technique, while the model parameters are determined based on the steady-state and transient characteristics. Finally, by analyzing the mechanism of virtual power loss, a constant initialization technique is proposed to calculate the historical current sources in different switching states. Taking a two-level voltage source converter as the experimental object, a real-time simulation hardware platform is built to verify the feasibility of the proposed model. Simulation results show that, compared with the traditional L/C constant admittance switch model, the virtual power loss of the proposed switch model is reduced by 92%, the oscillation time of the model is reduced by 20%~30%, and the constant initialization technique can completely eliminate the virtual power loss.