TThis study delves into optimizing process parameters in plastic injection molding, a critical manufacturing method for producing high-quality plastic products. Employing the Taguchi method, a renowned statistical tool, the research focuses on minimizing defects such as shrinkage in polypropylene containers. The critical parameters like melt temperature, injection pressure, packing pressure, and packing time are meticulously and comprehensively analyzed through a series of 27 experiments based on the L27 Orthogonal Array. The findings indicate that melt temperature is the most influential factor, followed by injection pressure, packing pressure, and packing time. Optimal conditions identified include a melt temperature of 260°C, injection pressure of 65 MPa, packing pressure of 50 MPa, and packing time of 10 seconds. Implementing these conditions significantly decreased plastic jars' defect rate, underscoring the Taguchi method's efficacy in process optimization. For optimizing process parameters, the energy usage is reduced by 14.685 kWh/day while CO2 is decreased by 58.74kg/day. This research provides valuable insights into the importance of statistical methods in improving manufacturing efficiency and product quality in the plastic injection molding industry for sustainable manufacturing practice along with minimizing environmental impact.