With the demographic transition and the deepening of population aging in China, the implementation effect of policy tools has been endowed with more uncertainty under the unprecedented complex implementation environment. This paper focuses on the effect of monetary policy in the aging economy. In our study, the aging rate is combined with the money in utility (MIU) model, which introduces the monetary policy in the Ramsey model. Under the framework of this theory, the influence mechanism of monetary policy on the aging economy is explored. The study shows that the effect of monetary policy on the aging economy is partly consistent with the MIU model, but there are particularities of the aging economy. Specifically, the monetary policy in the aging economy is still "super neutral". That is, the monetary growth rate only raises the production in short period, however, it has no effect on economic growth in long time. Yet, if monetary policy can work on the rate of technological progress, the effect of monetary policy may be "non-neutral" and inflation will also be weakened. © 2021, Editorial Board of Journal of Systems Engineering Society of China. All right reserved.