The production of methanol via the gasification of waste polyethylene offers a promising approach to plastic waste management and chemical production. This study utilizes Aspen Plus to simulate the gasification of waste polyethylene and subsequent methanol production. The simulation involves modeling the gasification reactor, the syngas treatment, and the methanol synthesis reactor. The effects of gasifier temperature, the steam-to-feed-mass ratio, and reactor pressure on methanol yield and purity are investigated. The results show that the Aspen Plus simulation accurately predicts the methanol production process, providing valuable insights into process optimization and design. The simulation results indicate that a gasifier temperature of 1000°C, a steam-to-feed-mass ratio of 0.5, and a reactor pressure of 50 bar yield a methanol purity of 99%. This study also examines the economic viability of the process, including the costs of the feedstock, energy, and equipment. The results demonstrate that the production cost of methanol via the gasification of waste polyethylene is competitive with that of the traditional methods. This study provides a comprehensive framework for simulating and optimizing methanol production from waste polyethylene, offering a valuable tool for industry and research applications. This study's findings have significant implications for the development of sustainable waste management practices and the production of clean energy. Future research will focus on scaling up the process.