The invention relates to a power grid reliability real time parallel assessment method base on Monte-Carlo simulation task dynamic distribution. Firstly, data are input, based on the De Moivre-Laplace central-limit theorem, a sampling frequency corresponding to LOLP index variance coefficient convergence of the system is estimated for conservative projection. Then, the task distribution is carried out according to the estimated value of the sampling frequency. After each processor receives a simulation task, N/p system states are extracted through parallel random number generators for carrying out fault result analysis to fault states of the same class so as to form reliable indexes in the N/p system states. Simulation results are sent to a major processor and tasks are finished, and the major processor immediately receives the simulation results sent by the processors after completing task%. The beneficial effects are that the method is high in simulation precision, the inter-processor communication frequency (or time) is also reduced while the convergence precision is ensured, and the Monte-Carlo simulation efficiency is further improved.