The invention provides a target obstacle longitudinal anti-collision method based on millimeter wave radar detection. The distance S between a vehicle and a front vehicle and the speed V1 of the frontvehicle are measured by the intelligent vehicle through a millimeter wave radar, the travelling speed V2 of the intelligent vehicle is read through a vehicle CAN bus, and the pre-collision time is Tp, wherein Tp meets the solution of Tp=S/(V2-V1); if the front vehicle is subjected to emergency braking, the collision time is T, wherein T meets the solution of T=S/V2+TTC; the collision time is divided into three stages and is obtained through real-time calculation, and when the time is 3-5 s, a buzzer is triggered to conduct alarming to remind a driver; when the time is 2-3 s, a braking valve is triggered, and the vehicle is subjected to buffering retarding braking; and when the time is within 2 s, the braking valve is triggered to make emergency braking. Additionally, on the basis, a distance S signal also serves as a reference, and when S is smaller than 3 m, the braking valve is triggered to make emergency braking. According to the target obstacle longitudinal anti-collision method,the intelligent driving vehicle can be driven more safely in a dynamic environment.