An anti-collision beam used before rolling of a small automobile is in an arc shape as a whole, and the cross section of the beam comprises three closed cavities which are arranged in an upper-middle-lower mode. The cross section of the front anti-collision cross beam is composed of the three closed cavities, the Y-shaped main supporting section with high stability is formed between the middle cavity and the cavities in the two sides, the double-layer wall thickness structure of the main supporting section can play a stable supporting role, and the bending resistance of the cross beam in the collision process is obviously improved; the structural design of the first reinforcing section, the second reinforcing section and the front reinforcing section in the cross beam section is beneficialto further improving the bending resistance of the cross beam. The cross beam is formed by rolling, and compared with a stamping process, the material utilization rate and the production efficiency are high; compared with a traditional B-type anti-collision cross beam, the weight of the cross beam body can be reduced by 10%-15% under the condition that the bending resistance is equivalent, and the purpose of light weight is achieved. The device is reasonable in structural design, easy to implement and mature in process, and has a good market prospect.