The choice of socioeconomic development pathways will affect the urban and rural development trend and bring a new urban and rural population distribution pattern in the future.Under the framework of IPCC Shared Socioeconomic Pathways (SSPs),this study applies the Sixth National Population Census data with consideration of demographic policy and current migration situation of mainland China to localize the fertility,mortality and migration parameters in the PDE model.Subsequently,the national and provincial scale urban and rural population in mainland China were projected under five SSPs.Research results show that:(1) urban population in mainland China will increase under the all five SSPs,with an increase of 220 million (SSP3) to 370 million (SSP5) people in 2015-2050.The rural population will decline continuously,with a decrease of about 110 million (SSP3) to 400 million (SSP5).The urbanization rate in mainland China will reach 67%-86% by 2050.(2) In the future,the urban population in the majority of provinces will increase,with the higher growth rate in the provinces of western China than eastern provinces.On the contrary,rural population of all provinces of mainland China will reduce significantly,with the decrease being more obvious in eastern provinces than that in western provinces.With relative to 2015,urban population in provinces including Tibet,Xinjiang,etc.can increase by more than two times in 2050.Meanwhile,rural population of most provinces will reduce by more than 60%.(3) In the future,the effect of natural growth on both urban and rural population will gradually change from positive to negative.The mechanical growth will have a positive effect on increase of urban population but negatively effects the size of rural population with a gradual decreasing impact.The difference of natural variability between eastern and western provinces is the main factor leading to the different changes of urban and rural population.