With the continuous development of distributed photovoltaic （PV），the risk of voltage limit violation and the problem of power quality degradation in the distribution network are becoming increasingly serious.Therefore，a method of weak point identification for distributed PV access to the distribution network based on the time-varying Copula function is proposed，and risk assessment is performed on it.The correlation of distributed PV output is analyzed to identify vulnerabilities in power system component states，and the distribution network reliability is enhanced.First，a time-varying Gaussian Copula function is employed to analyze the force output correlation of distributed PV，achieving complex function sampling and accurately describing the distributed PV correlation.Subsequently，a linearized model derived from the Newton Raphson power flow calculation method is adopted to simplify and solve the complicated nonlinearized problems.Furthermore，a quantitative method based on repeated power flow calculation is proposed for evaluating the reliability of the system，and the utility theory is used for identifying the weak links of components.Finally，simulation experiments are conducted on the proposed method by means of the modified IEEE 33 node system.The results demonstrate that the accuracy of distributed PV output can be improved by the proposed method.Additionally，a quantitative analysis is conducted on the effects of different distributed PV penetration ratios on the operational risks of the power system.