Synchrotron radiation infrared (SRIR) light has the advantages of wide spectral range, small divergence angle, high brightness, and high signal-to-noise ratio. Combined with traditional infrared spectroscopy technology, SRIR microspectroscopy technology is used in infrared spectroscopy microscopy for samples, and the micron-level spatial spectral information of samples can be obtained. By taking an MiTeGen polyimide loop as the sample and using SRIR light from line station BL01B1 of Shanghai synchrotron radiation facility as the light source, we perform the synchrotron radiation infrared three-dimensional (3D) microspectroscopy experiments based on point scanning method. The two-dimensional microspectral information of the MiTeGen polyimide loop under different angles is collected based on point scanning method. The microspectral information in the wavenumber range of 1495--1485 cm ^-1 is selected, SRIR 3D microscopic reconstruction is performed by using algebraic iteration algorithm for the amide Ⅱ chemical component of the polyimide ring, and a whole 3D reconstruction image is obtained. The research shows that this method can reconstruct the 3D infrared microscopic structure of the sample's chemical components with a high signal-to-noise ratio.