The invention discloses an estimation method for a reliability index of a DC power distribution network, and the method comprises the steps: defining a new estimation index for new energy reliabilityin the DC power distribution network, wherein the defined new estimation index includes a new energy loss-of-load frequency (NELOLF) index, a new energy loss-of-load time expectation (NELOLE) value, anew energy loss-of-load probability (NELOLP) index and a new energy power loss expected value NEEENS; carrying out the reliability evaluation calculation of the DC power distribution network throughcombining with traditional estimation indexes and defined new estimation indexes, and obtaining various types of indexes; carrying out reliability comprehensive estimation calculation based on the traditional estimation indexes and the weight of the defined new estimation index in the DC power distribution network, and thus establishing a reliability value function model. The method introduces thequantification of new energy reliability, and is used for research of the reliability estimation of the DC power distribution network giving consideration to the new energy grid-connected power generation.