In the course of the development of Beijing, the rapid growth of population has posed great pressures of water resources shortage and water pollution to Beijing. The effect of population change on the consumption of water resources in Beijing was studied by analyzing population and water environment data in Beijing from 2004 to 2011. The results showed that: 1) the household registration population of Beijing increased by 1.15 million from 2004 to 2011, the floating population in Beijing grew by 4.843 million during the same period, and the annual average water consumption almost increased by 141 million m³; therefore, the high-speed growth of population is the fundamental reason for years of growth of the total consumption of water resources in Beijing; 2) at the end of 2011, the total number of the primary industry practitioners was barely 0.591 million, which was less than 1/10 of that of the tertiary industry practitioners; the total number of the secondary industry practitioners was less than 1/3 of that of the tertiary industry practitioners; in other words, the tertiary industry has replace the primary and secondary industries, becoming a pillar industry in the city; 3) during this period, the annual average water consumption per capita for domestic, agricultural and industrial purposes dropped by 8.4, 37.7 and 27.1 m³ respectively; the optimization of the industrial structure has made the annual average water consumption per capita in Beijing show a yearly declining trend. Controlling population growth and deepening the industrial structural adjustment are effective ways to realize the sustainable development of water resources in Beijing.