The invention provides an extra-high voltage direct current risk assessment method based on a power grid risk and equipment reliability. The method comprises the following steps: grading the influenceof an extra-high voltage direct current real-time operation state on power grid safety; determining an extra-high voltage direct current risk state according to the operation reliability and the divided grades of the extra-high voltage direct current; and issuing early warning according to the extra-high voltage DC risk state. The invention provides a technical scheme. The method can be used forreal-time monitoring and early warning of the extra-high voltage direct current power transmission system, assists scheduling operation personnel in knowing the extra-high voltage direct current operation state and main risks in time, performs corresponding pre-control operation in advance, and greatly improves the risk perception and pre-control capability of regulation and control operation personnel on the extra-high voltage direct current system of long-distance and high-capacity power transmission.