The invention discloses a vibration suppression method for a steel rail welding head straightness detection system. The vibration suppression method comprises the following steps of S1, establishing a servo motor mathematical model, performing Laplace conversion on the servo motor mathematical model, and combining with a current ring to obtain a servo motor transfer function; S2, establishing a drive system mathematical model according to a relation between working platform displacement and servo motor output displacement, and performing Laplace conversion on drive system mathematical model to obtain a transfer function of a working platform; and S3, an input instruction, after being subjected to input shaping in the steps S1 and S2, and PID regulation in a servo motor control link, controlling the drive system to move. By adoption of the vibration suppression method, noise signals in detection data and data processing difficulty can be reduced while the detection efficiency and detection result accuracy are improved; and the vibration suppression method is wide in applicable range, simple in design, and relatively high in industrial application value.