The accurate prediction of population aging process in a country or region is an important basis for the establishment of corresponding macropolicies. Stochastic process in grey prediction is regarded as time-dependent grey process within a certain range of variation. According to GM (1,1) modeling mechanism, the prediction models of the number and the proportion of aging population in Qingdao City are set up. The number and the proportion of the aging population from 2009 to 2040 are attained based on the prediction models.The number of the aging population in 2035 will be double the one in 2009.The causes of the population aging of Qingdao City are analysed. The first cause is the impact of the two birth booms of Qingdao City between 1950s and 1960s. Secondly, the proportion of youngsters population is reduced as a result of the birth control from the beginning of 1970s.The corresponding countermeasures are put forward ,such as extending gradually the length of work and raising the retirement age to solve the problem of labor shortage, and establishing perfect old-age social security system of the city and the countryside.