As China is moving rapidly toward the aging society, the aging population is becoming larger and larger.In this case, a tourism market targeted at the elderly has attracted great attention due to its high profit.How big on earth this profitable cake is has become a great concern of thousands of tourism corporations and it is also the crucial information for those agencies to make new marketing strategies.Firstly this paper listed and inducted all the elements involved in the tourism market and then made mathematical analysis on the connections among different elements.Then based on those analysis the senior tourism market capacity model was built.Of those elements, purchasing power is considered as a key one.So in order to minimize the effect of uncertainties during the process of building model, linear regression model and ARIMA model were built specifically to analyze and predict the purchasing power, which could provide relatively more accurate basis of decision for Chinese tourism corporations in their future marketing practices.