Abstract: A method for constructing a finite element interpolation function and a system thereof are provided, relating to a technical field of analog simulation, so as to improve performance of the interpolation function. The method includes steps of: constructing an interpolation function through a hybrid coordinate system formed by a linear transformation coordinate system and an isoparametric coordinate system; and according to characteristics of a target solid element, determining a coordinate variable number, a term number and an order of the interpolation function, wherein: the characteristics of the target solid element include a known node number and a known node displacement component number; and, the term number of the constructed interpolation function is equal to a total displacement number of related interpolation nodes of the target solid element.