Abstract: This paper studied the quantitative detection and analysis of layered damage with different depths and sizes in carbon fiber composites based on phased array ultrasonic technology. Damage samples with different depth damage of 3.5, 4.5, 5.5, 6.5, 7.5 mm were designed and prepared for delamination damage of carbon fiber composites. The phased array ultrasonic testing technology was used to detect the damage of ϕ2.0, ϕ2.5, ϕ2.0, ϕ3.5, ϕ4.0, ϕ4.5, ϕ5.0, ϕ6.0, ϕ7.0 mm respectively by A, B and C scans. Finally, the impact damage sample was detected. The location, shape and size of the layered damage of carbon fiber composites at different depths could be intuitively expressed by phased array ultrasonic B scan and C scan images. The damage test depth could reach 7.5 mm, which could detect the minimum diameter of ϕ2 mm delamination damage. The detection results of real impact damage were clear.