The widespread use of plastics has reshaped material cycles, requiring systematic understanding of their socioeconomic metabolism, encompassing material flows and stocks from production to end-of-life, to support effective policy development. Although previous studies have addressed specific aspects of plastic flows in China, existing data have been fragmented, with limited resolution and temporal consistency. Here, we develop a high-resolution, temporally consistent dynamic material flow database for China (1978-2022), covering 20 major plastic types (covering over 95% of national demand), 11 manufactured product groups, 9 end-use sectors, 4 waste disposal pathways, and international trade. The dataset is validated against published estimates and further assessed through sensitivity and uncertainty analyses, which highlight key parameters that are relatively sensitive and suggest directions for future refinement. By openly releasing all underlying data and code, we ensure full transparency and reproducibility. This work provides a database of over 60,000 data records that serves as a critical basis for quantitative research on plastic material cycles and supports further modeling of circular economy strategies.