The new quality productive forces, as an advanced form of productive forces distinct from traditional ones, with advanced technologies, outstanding efficiency and high quality, align with the development concepts of the new era. Cultivating and enhancing the new quality productive forces has become an important force driving China's economy towards high-quality development. Based on the perspective of supply chain, this paper studies the impact of digital transformation of downstream companies (customers) on the new quality productive forces of upstream companies (suppliers) and its mechanism. The annual reports of A-share listed companies from 2012 to 2022 are used as samples to construct the digital transformation text retrieval keyword database, and the logarithmic word frequency is used as the digital transformation index. Using the related indicators of A-share listed companies from 2012 to 2022, the entropy method is used to construct the index of new quality productivity level, and the annual data of the new quality productivity level of upstream enterprises and the digital transformation level of downstream enterprises are matched and analyzed by regression. The empirical results show that the customer digital transformation significantly improves the supplier's new quality productivity level, and the customer digital transformation mainly affects the supplier's new quality productivity level by optimizing the supplier's supply management efficiency and the supplier's customer voice.