Abstract: Experiments were carried out to compare the static strengths and fatigue behaviors of the carbon fiber/bismaleimide (BMI) resin composite flat-joggle-flat (FJF) joints under a certain adhesive thickness. Meanwhile, effects of the adhesive thickness on the mechanical properties of the carbon fiber/BMI resin composite FJF hybrid joints were explored. Backface strain technology was used to detect the adhesive cracking at the end of the overlap zone. Adhesive stress distributions in the overlap zone of the carbon fiber/BMI resin composite FJF hybrid joints were analyzed based on the ABAQUS software. The results show that the average tensile ultimate load, the average adhesive cracking cycles at the end of the overlap zone and the average fatigue life of the carbon fiber/BMI resin composite FJF hybrid joints all rise with the increasing adhesive thickness in a certain range of 0.1 mm to 0.3 mm. The carbon fiber/BMI resin composite FJF hybrid joints with different adhesive thicknesses all go through the same failure stages: Firstly the adhesive cracking happens at the end of the overlap zone, then the adhesive crack extends along the overlap zone, finally a net-tension failure occurs at the hole near the loading end, presenting the fracture appearance of ±45°. As the adhesive thickness increases within the range of 0.1 mm to 0.3 mm, adhesive peel and shear stress at the end of the overlap zone and the compressive stresses around the bolt hole all decrease. Shear stress is the main factor that accounts for the adhesive failure.