Abstract: The construction of low-carbon cities is a pilot policy to promote energy conservation and emission reduction, achieve China's 2030 carbon peak goal and comprehensive green transformation of economy and society. Promoting the progress of green technology is an important starting point to achieve the goals of emission reduction and green development. However, the existing literature rarely discusses the spatial correlation effect of green technology progress from the perspective of network, and fails to reveal the spatial path of green technology progress. Based on the authorized patents of Chinese green invention from 2005 to 2020, a patent citation network is constructed, and the progress and spillover of urban green technology are characterized by the number of urban patent citations and citations respectively. The impact of the pilot policy of low-carbon city on urban green technical progress and spillover by using a vary-difference-in-difference model, and analyze factors of urban green technology progress such as the source, target and participants. The result shows that the pilot policy of low-carbon city significantly promoted the progress and spillover of urban green technology. This conclusion is still valid after a series of robustness tests such as parallel trend test, PSM-DID test and placebo test. At the same time, the pilot policy of low-carbon city mainly promotes cross regional green technology progress and spillovers, and has a stronger impact on high-level administrative cities and their surrounding pilot cities; The pilot policy of low-carbon city has a stronger effect on the progress and spillover of green technology in high pollution industries; The pilot policy of low-carbon city has a slightly higher impact on the progress and spillover of green technology of enterprises than non-profit institutions such as scientific research institutes.