Couples will now be allowed to have two children, it said, citing a statement from the Communist Party.
The controversial policy was introduced nationally in 1979, to slow the population growth rate.
It is estimated to have prevented about 400 million births. However concerns at China's ageing population led to pressure for change.
Couples who violated the one-child policy faced a variety of punishments, from fines and the loss of employment to forced abortions.
Over time, the policy has been relaxed in some provinces, as demographers and sociologists raised concerns about rising social costs and falling worker numbers.