The invention discloses a method and system for evaluating the reliability of a power distribution network containing distributed type new energy, and relates to the technical field of new energy power generating. According to the method, firstly, the probability distribution characteristics of wind speed and solar irradiance is described by the Weibull distribution and the Beta distribution, and an active power model of output or consumption of a wind power plant, a photovoltaic power station and a load is established; and then the power system is subjected to probability discretization to quantitatively express the available capacity of the components in different states and the corresponding probability in a power system; and finally, for all possible state combinations of the wind power plant, a photovoltaic power plant and load components, the optimization problem of minimum slack variables is solved to achieve the fast and accurate estimation of the reliability of the power distribution network. LOLP (loss of load probability) and EENS (Expected Energy Not Served) are selected as reliability estimation indexes to guarantee the calculating precision and simultaneously substantially reduce the time cost for the calculating.