Abstract: China's population trend would be actively addressed by the universal two-child policy. This paper gives the population prediction based on the constant population policy. The conclusions are as follows:The new policy will not bring a sharp rebound in fertility and population size, the peak difference of newborn population before and after the policy will be over 4 million; policy adjustment will improve the peak population and structure, delay the labor supply decay, but a negligible role. From the experience of other countries, the trend in fertility decline seems inevitable. Therefore, the universal two-child policy is not the end of the policy adjustment. It will continue to monitor fertility level, further adjust the population policy; establish and improve the “family friendly” policy system; cope with the negative effects from the social system and the economic system.