Abstract: Data from 1978 to 2002 and a state space model are used to make empirical study for the consumer behavior of Chinese urban residents. The main conclusions are: First,before 1990 the long-run ratio between consumption and income was relatively stable; however, after 1990 beth long-run MPC and long-run APC have been declining continuously. Secondly, affected by the declining ratio of long-run Equilibrium,trends of consumption and income have turned to be.