A semiconductor structure and a method for forming the same are provided. In one form, a forming method includes: providing a base, a gate structure, a source-drain doping region, and an interlayer dielectric layer; removing the gate structure located in an isolation region to form an isolation opening and expose the top and side walls of a fin located in the isolation region; performing first ion-doping on the fin under the isolation opening to form an isolation doped region, a doping type of the isolation doped region being different from a doping type of the source-drain doping region; and filling the isolation opening with an isolation structure after the doping, the isolation structure straddling the fin of the isolation region. In embodiments and implementations of the present disclosure, the isolation doped region is formed, a doping concentration of inversion ions in the fin of the isolation region can thus be increased, and a barrier of a P-N junction formed by the source-drain doping region and the fin of the isolation region can be increased accordingly, to prevent the device from generating a conduction current in the fin of the isolation region during operation, thereby implementing isolation between the fin of the isolation region and the fin of other regions. Moreover, there is no need to perform a fin cut process. Hence the fin is made into a continuous structure, which helps prevent stress relief in the fin.