Abstract: The marginal revolution in the early 1870s and the subsequent marginalist economics shed great impact on the development of economics in later days. However, up to now, there have been controversies among economists on why and how the marginalist revolution started. It is considered critical to clear up these controversies for a thorough understanding of marginalist economics and the principle of economics evolution. Starting from the pioneers of marginalist economics, this paper puts up new arguments, i. e., the marginal revolution is the result of the interaction of multi-disciplinary subjects and the integration of subjective and objective factors.