A computer-readable storage medium storing a multilayer fluid analysis program is provided for analyzing a multilayer fluid on a feed block type T-die as 2.5 dimensions in which each layer is divided into elements. The program causing a computer to execute: a layer thickness calculation process for calculating the layer thickness under a condition that stresses in a normal direction and a tangential direction equilibrate on an interface of each layer and a flow velocity on the interface is continuous, without considering a fluid flow in a thickness direction, considering a viscoelastic effect of a fluid to analyze an encapsulation phenomenon, and based on a shape of the feed block and a second normal stress difference of resin assuming that a layer thickness in a transverse direction fluctuates in a developmental state; and a display process of displaying a calculation result of the layer thickness calculation process.