Delay discounting is the decrease in subjective value of a reward as the interval of receiving it is increased. Previous studies have found inconsistent results on the relationship between age and delay discounting, and few studies have been conducted using Chinese participants. The current study aimed to clarify this relationship using a relatively large sample of Chinese adults with a wide age range (viz., 18 to 86 years old). A total of 1288 individuals completed the Monetary Choice Questionnaire. Results showed that the rate of delay discounting increased with age across adulthood, with younger participants (18–30 years) discounting less than both middle-aged participants (31–60 years) and older participants (over 60 years); and middle-aged participants discounting less than older participants. Furthermore, when the reward magnitude was large, participants were more likely to wait for delayed rewards. The increase in delay discounting rate from middle-aged adults to older adults might be explained by the life-cycle theory. The increase in delay discounting rate from young adults to middle-aged adults may reflect that young adults expect much time and a variety of future positive life events in the rest of their lives.