The invention discloses a preparation method for a poly-p-phenylene benzobisoxazole (PBO for short) fiber reinforced resin matrix composite material. According to the method, the PBO fiber reinforced resin matrix composite material is prepared by adopting a wet-process winding forming technology, and an online ultrasonic treatment device is introduced in the preparation process; the device is simple to install, easy to disassemble, convenient to operate, capable of performing production continuously and high in production efficiency; and the parameters and the installation position of the online ultrasonic treatment device can be adjusted, and therefore the improvement of the fiber infiltration quality of resin can be realized. The method can be used for preparing wet-process winding formed composite products, such as pressure vessels and pipelines and can also be used for preparing prepregs serving as intermediate materials of hot-press formed composite products. Compared with a composite material prepared by a traditional method, the PBO fiber composite material prepared by the method has the advantages that the defects are few, the interface bonding performance is high, and particularly the interlaminar shear strength can be obviously improved, and therefore the problem that the interlaminar performance of the PBO fiber reinforced composite material layer is poor can be solved, and the use performance and application benefits of the PBO fiber reinforced composite material can be effectively improved.