China’s rapid population growth after 1949 has crucial implications for its economy. This study examines the impact of semi-dwarf rice on population dynamics during the collective era. Results show that the introduction of semi-dwarf rice significantly increased grain production and reduced the death rate, while leaving the birth rate unaffected. Semi-dwarf rice caused a larger decline in the death rate for counties under high population pressure, suggesting that it improved health by alleviating hunger. The rural population was able to benefit from semi-dwarf rice because of stable procurement rates and increased grain prices.