The urban population in the Chinese mainland has surpassed the rural population for the first time, accounting for 51.27 percent of the total, the National Bureau of Statistics announced Tuesday.

Official statistics showed that the urban population in 2011 reached 690.79 million, an increase of 21 million from 2010, and the rural population is 656.56 million, Xinhua reported.

"Judging from the statistics, this historic milestone helps China rid itself of the title of a large agricultural country," Lu Jiehua, a professor with the Department of Sociology at Peking University, told the Global Times.

Li Peilin, director of the Institute of Sociology at the Chinese Academy of Social Sciences (CASS), also said that it marks a turning point in China's population structure, which has been characterized by an overwhelming rural population for thousands of years, and is a great event in the country's urbanization, China National Radio (CNR) reported.

Profound changes will occur in Chinese people's lifestyles, mode of production, occupational structure, consumption habits as well as values, Li was quoted as saying.

A blue paper analyzing and predicting trends in Chinese society was released by the CASS last month, pointing out that issues of residence are currently the main reasons causing instability in the urbanization process.

"The population flow from rural to urban areas resulting in the separation of family members means the real urbanization process cannot be maintained," said the paper, which Lu said also reflects the country's difference with Western countries in urbanization.

He said that there are more than 200 million people making up the floating population in China, who were born in the countryside, live and work in cities, but who don't enjoy the same services and benefits as other city dwellers.

"In Western countries, urban residents are those who have completely left the countryside and enjoy the same treatment as other city residents," said Lu.

"But we have included the floating population into our urban population," he added.

According to statistics cited in the CNR report, the percentage of the floating population that enjoys social welfare is much lower than that of city natives.

Only 30.2 percent of the former are entitled to endowment insurance, while for city dwellers, the number is about 63.1 percent.

"More rural people coming to cities is an inevitable phenomenon caused by industrialization, which also shows the economic development of a country," said Lu. "But problems brought by the trend should not be neglected."

He said that most rural residents who go to cities are strong young, laborers. Their leaving will not only negatively influence rural development but also exacerbate the problem of supporting the elderly population in the countryside.

"It is correct to let urban development drive social development. But we should not increase the distance between rural and urban areas," he said.

"In the future, all levels of government should think more about the use of rural land and how to improve the elderly rural population's living conditions."