By applying the Herfindahl–Hirschman Index (HHI) to measure the degree of unification during each of China’s historical periods, we find that since 770 BCE, periods of higher unification are associated with lower frequencies of external war and fewer military technological innovations per 10 million population per 100 years, suggesting that unification stifled the demand for new technology through the reduced threat of foreign wars. Internal conflicts, however, created a negative impact on military technological innovations, possibly because domestic rebellions could be better addressed through governance reforms rather than hardware innovations. To provide specific macro evidence, we focus on where bronze technology was initially applied after its introduction to China in the early second millennium BCE. Our archaeological data shows that from 1700 to 221 BCE, bronze grave objects first appeared in regions with frequent wars; furthermore, from 770 to 221 BCE, these regions had significantly higher ratios of military to all bronze grave objects, exhibiting higher demand for bronze, and the new technology of the time.