The utility model provides an air-to-liquid type braking clamp unit with a parking braking function. The air-to-liquid type braking clamp unit is characterized in that a spring braking piston where a piston rod penetrates through is arranged in a spring braking barrel, a common braking piston is connected to one end of the piston rod, the spring braking barrel is divided by the spring braking piston into a common braking cavity and a parking braking cavity, a common braking cylinder body is arranged in the common braking cavity, the common braking piston is arranged in the common braking cylinder body, a first air inlet is formed in the common braking cylinder body, and a second air inlet communicated with the parking braking cavity is formed in the spring braking barrel; a hydraulic cylinder is connected to the spring braking barrel and is provided with a piston cavity, and the other end of the piston rod is arranged in the piston cavity in a penetrating mode; a clamp assembly is provided with two clamp bodies, brake lining supports are arranged on the two clamp bodies respectively, and pressure cavities communicated with the piston cavity are formed between the braking lining supports and the clamp bodies. By means of the air-to-liquid type braking clamp, common air pressure is converted into liquid pressure so as to finally act on a braking disc, and larger braking output force can be achieved.