Tensile experiments on adhesively scarf-repaired composite laminate joints were conducted, for analyzing the stiffness, strength, failure modes and key positions' strain distributions of the joints with different scarf angles and extra ply numbers subjected to unidirectional tensions. A kind of carbon fiber woven reinforced composite was applied to fabricate the base laminates and repair patches, and a kind of curing modified epoxy supported film adhesive was used as adhesive layer, designing a series of specimens with one extra ply or two extra plies, of which scarf angles are equal to 1.8°, 2.6°, 3.5° and 4.4°, respectively. Tensile experiment results show that stiffness and strength of the joints are negatively related to scarf angles in the range from 1.8° to 4.4°. Adding extra plies helps enhancing the stiffness and strength of the joints. The failure modes of the joints can be summarized into four types, which are related to scarf angles and extra ply numbers. The longitudinal strain changing at the key points of the joints can be applied to reflect the failing process of the joints dynamically.