Power grid enterprises have a large number of investment projects and large amounts, and their investment decision-making is a more complex work, which needs to weigh many influencing factors and objective functions, and consider how to make reasonable capital allocation. With the continuous evolution of the global energy landscape and the rapid development of renewable energy technologies, the importance of the power grid, as a key infrastructure connecting energy production and consumption, is self-evident in its investment optimization decisions. In the face of the increasing energy demand and the dual pressure of environmental protection, how to rationally allocate resources and choose the best investment projects has become an urgent problem to be solved in the power industry. In this paper, we will discuss the application of RWCS (Random Weight Combination Screening) search algorithm in power grid multi-project portfolio investment and its optimization decision-making effect. MATLAB simulation shows that under certain evaluation criteria, the RWCS search algorithm is better than the cuckoo search algorithm for the capital allocation accuracy and capital allocation reliability of the investment projects of power grid enterprises.