A coordinated planning method of source load storage flexible resources for photovoltaic access to the power system is proposed to improve the operation stability and economy of the power system. The basic operation characteristics of PV-connected power systems are analyzed from the perspectives of power flow, voltage, and frequency. According to the analysis results, a resource coordination planning model is built to determine the cost, the lack of flexibility to adjust the cost, and other objective functions. On this basis, the corresponding constraints are proposed and solved by the ant colony algorithm to achieve flexible resource coordination planning. The experimental results show that compared with the existing methods, the proposed method has a higher confidence level of flexibility requirements, indicating that it has a higher energy storage and regulation capability.