Disclosed are a Raman spectrometer sample platform and a method for testing a light spectrum in situ thereby, used for providing the Raman spectrometer with a horizontal magnetic field environment. The sample platform comprises: a base (10); magnetic brackets (4) fixed on the base (10); a first magnet (5) and a second magnet (7) which are installed on the magnetic brackets (4) and are correspondingly arranged for generating a horizontal magnetic field; a placement block (6) which is arranged between the first magnet (5) and the second magnet (7) and is used for placing a sample; and the placement block (6) is arranged in the middle part of the sample platform, and the magnetic brackets (4) are respectively located at two sides of the placement block (6). The sample platform can be directly placed on an object stage of the Raman spectrometer to provide experimenters with experimental conditions that can acquire Raman light spectrum data of the sample under different magnetic field intensities.
