Abstract: Digital economy security is the basic premise of the digital economy development and an important guarantee for the sustainable development of new quality productive forces. Based on the security needs of new quality productive forces and the novel connotations of digital economy security, this paper constructs an evaluation index system at the municipal scale by integrating three dimensions: digital, economic, and institutional, and uses the entropy weight TOPSIS method to measure the digital economy security levels of 278 prefecture-level and above cities in China from 2011 to 2022. Additionally, this paper employs Dagum Gini coefficient, kernel density estimation, Markov chain analysis, geographic detectors and spatial econometric model to deeply analyze the space-temporal evolution patterns and driving factors. The study shows that: (1)The level of digital economy security in whole China exhibits an upward trend, with significant improvements across the eight major comprehensive economic zones; (2)The global and balanced characteristics of China's digital economy security have become increasingly prominent, showing a gradual narrowing trend in internal disparities across regions and nationwide; (3) China's digital economy security demonstrates a trend of multi-polarization, with a few coastal cities leading at the national level; (4) China's digital economy security level exhibits the "club convergence" phenomenon, with significant neighborhood effects; (5) Economic foundation, financial conditions, university construction, knowledge flow, government attention and public supervision significantly affect the temporal and spatial evolution of China's digital economic security level, and the effect is significantly different. Among them, knowledge flow demonstrates a relatively stronger driving force and exerts a positive spillover effect within this dynamic system. Based on these, this paper proposes measures such as deeply integrating the elements of new quality productive forces, fully leveraging the leading role of benchmark regions, implementing precise policies in line with local conditions, and constructing a co-governance framework for digital economy security, with the aim of promoting a comprehensive and coordinated improvement of digital economy security in China.