A Raman detection system has a Raman spectrometer and a fixing light shielding stand. One end of the fixing light shielding stand is fixedly connected to the Raman spectrometer, and the other end is disposed with an entrance groove for a needle-like SERS probe to enter. A slot for fixing the needle-like SERS probe is formed at an end of the entrance groove, and the slot and the needle-like SERS probe match in shape and size. The Raman detection system has a fixing light shielding device with a dark color groove and a focal length. The groove can be used for limiting the rolling of the curved surface structure of the needle-like SERS probe. A laser can be focused on the curved surface more accurately by adjusting the distance from the instrument detector to the SERS probe.