This paper optimizes the layout design of optical resource monitoring node networks via a comprehensive evaluation standard composed of the shortest network path, coverage and time-space zoning and ensures the optimal economic and reasonable layout of the monitoring network. At the same time, this paper presents a method, such as Zigbee and fourth generation (4G) designs, for monitoring the solar resources of large PV power stations based on wireless sensor technologies and implements a solar resource monitoring system of a large-scale PV power plant group based on wireless sensor technology. Compared with the solar resource monitoring networks before optimization, the optimal layout and wireless sensor networks have less redundancy of information through correlation analysis and rotational empirical orthogonal function (REOF). The reliability and coverage increase by using the theory of the shortest network path to select routing nodes and decide the effective coverage range. Through theoretical analysis and empirical verification, it is also shown that the proposed optimal layout of the solar resource monitoring network can meet the assessment accuracy of the power generation capability of large-scale PV power station groups and provide a reference for the expansion planning of large-scale PV power station groups.