Government policies and investments in photovoltaic (PV) research and development (R&D) have contributed to the rapid development of a PV industry through technology push in most countries over the past decade. It is worth investigating the effectiveness of investment-drive R&D policies at a global level, particularly how they work in reducing the costs of PV technologies. This study constructs a learning curve model to assess the performance of PV R&D policies in China, Germany, the United States and Japan. Market information—for example, PV module production, PV installation and PV technology improvement—is utilised to analyse how these policies take effect. The results show that PV R&D investments are efficient in decreasing the production costs of PV modules, which positively affects the development of PV module markets. However, weak PV technology conditions (including conversion efficiency, reliability) and low PV electricity penetration levels have resulted in surpluses in PV module markets, as well as PV electricity curtailment around the world. It is suggested that future R&D policies should contribute more to improving conversion efficiencies (the structure of technology push power) and grid integration technologies (demand pull power) for PV systems.