This study examines how stone-grinding technology accelerated the growth of complex societies in Neolithic China (8000–2000 BCE) primarily through the war channel rather than the productivity channel. Utilizing data from the China Archaeological Database (CADB), where large settlements (≥10 hectares) indicate complex societies and stone weapon grave goods proxy stone grinding’s battlefield applications, we find that grid cells with more stone weapons were more likely to develop large settlements and to have a greater area covered with such settlements, based on a panel dataset of 487 100 km × 100 km grid cells in China Proper across six millennial subperiods. By contrast, stone farming tools did not exhibit such a significant influence on large settlements, indicating that technological innovation drove complex societies primarily by amplifying the war threats rather than boosting agricultural productivity. Empirical evidence shows strong correlations between stone weapons and war-threat indicators, including military grave goods, fortifications, and violence-caused skeletal injuries. Instrumental variable analysis—using bone weapons and stone mines—not only demonstrates that accumulated experience in grinding and polishing bone weapons facilitated the subsequent adoption of ground stone weapons but also provides suggestive causal evidence linking stone weapons to the growth of large settlements. Even after 2000 BCE, bronze and iron technologies continued to shape complex societies through the war channel. Our results remain robust after accounting for population proxies, precipitation conditions, agricultural development, and potential irrigation demand.