Abstract: It has been more than 100 years, spanning three centuries since Dupuit proposed the steady well flow model and the Dupit formula. Due to the simple principle and the concise formula, Dupit formula is still in use. However, there have been a lot of disputes and misunderstandings about Dupuit's model, Dupuit's formula and relative concepts. Through analyzing Dupuit model and Dupit formula, this paper points out that the Dupuit model and the formula itself do not contain the concept of radius of influence. The concept of the influence radius was understood as one of aquifer parameters, trying to seek a representative average influence radius is lack of enough theoretical basis.