The emergence of the direct current point of common coupling (DC-PCC) brings about new difficulties to the simulation and analysis of voltage sourced converter-based multi-terminal direct current (VSC-MTDC) system. To solve this problem, this paper proposes a unified model to calculate DC-PCC voltages and DC line currents by means of quasi-admittance matrixes. The model consists of differential equations of DC-PCC injection currents and line currents and quasi-admittance matrixes are established to update the MTDC system. Thus the simulations and eigen-analysis of VSC-MTDC can be carried out by using the proposed model. On this basis, a simulation methodology of AC/DC hybrid system containing DC-PCCs is derived. Finally, the proposed method is verified in a 3-terminal 1-PCC system and a 4-terminal 2-PCC system. The simulations are consistent with the eigen-analysis results, which demonstrate the correctness and feasibility of the methodology. The analysis indicates that oscillations after faults in different systems have different dynamic performances while different DC topologies and DC-PCC numbers have little influence on system small-signal dynamics.