The mainstream design of the industry has not yet emerged, often resulting to lack of accurate market focus for the combination of technologies. Therefore, advanced leading vendors face the choice of patent portfolios and core technologies. Creating competitive advantages in R&D portfolios are extremely challenging. This study integrates patent statistics; comparing Patent Share (PS) and Revealed Technology Advantage (RTA) so as to measure the company's core technologies and identify the strengths of advanced R&D portfolios in the photovoltaic industry. Research shows that at the present stage, in the single-field study, most companies invest in R&D, followed by a-Si, and μc-Si. At the same time, compounds and patents in the a-Si region are applied across two specific technical fields. The advantages and capabilities of R&D portfolios are lower than those of leading companies that choose a single core technology in a specific technology area. Therefore, some companies will research the application of a single patent in two technical areas. This study provides a method for selecting core technologies for advantage analysis and promoting the decision-making quality of vendor technology planning, and helps the photovoltaic manufacturers to monitor the core technical capabilities among competing companies.