In this study, two-scale tensile analysis of a dovetail joint for a fan blade made of a carbon fiber-reinforced plastic (CFRP) is conducted to investigate macroscopic and microscopic behaviors of the dovetail joint. To this end, the two-scale analysis method developed by the authors is implemented in the finite element analysis software Abaqus with its user subroutine function. The present method is then applied to the two-scale tensile analysis of a dovetail joint consisting of a dovetail of a multi-directional CFRP laminate and a dovetail slot of a metal. In this analysis, material nonlinearity (viscoplasticity) of the matrix resin is explicitly considered. It is shown from the analysis results that high mode I tensile stress and mode II shear stress respectively occur at the area just above the contact surface between the dovetail and slot and at the area around the upper end of the contact surface, both macroscopically and microscopically. It is also shown that, even though the macroscopic load-displacement relationship is almost linear, the epoxy resin clearly exhibits nonlinear viscoplasitc deformation microscopically, which can cause inelastic deformation-induced fatigue damages and delamination.