A laser-assisted pulsed discharge method for generating plasma in water is proposed. Combining with the classical Drude model, a two-dimensional fluid mathematical model of the plasma generated by laser injected into the water pulsed discharge system is established, and the corresponding mathematical equations are given. The COMSOL Multiphysics software is used to simulate the interaction process between charged particles and laser vertically injected into the plasma channel, The local electron density when the laser with a certain energy is applied to the water dielectric pulse discharge system is studied. The preliminary simulation results show that the peak value of electron density increases from 1.65 × 10²¹ m^-3 to 8.29 × 10²¹ m^-3 when a laser with 50 mJ energy and 0.1 mm spot diameter is added into the plasma channel. This process plays a significant role in improving the ionization rate of plasma, which indicates that the technical scheme of laser assisted pulse discharge in water to generate plasma is feasible.