In response to global environmental and climate challenges, the development of a circular economy, particularly in reducing plastic harm, has become a global imperative. This study examines the factors influencing the development of a plastic circular economy in Taiwan, using PEST analysis to identify influences on industry and market performance in plastic reduction from 1991 to 2020. The findings reveal that both restrictive and encouraging political policies effectively aid in plastic reduction, although the impact of economic growth on reduction efforts is less clear. Socially, female demographics and increased environmental awareness significantly enhance plastic reduction. Technological advancement, despite being relatively lagging in Taiwan, significantly aids in these efforts. This research offers insights for policy and management strategies in transitioning the plastic industry towards a circular economy, providing guidance for government and industrial manufacturers.