Micro/nano periodic structures are generally adopted in diffraction gratings. As an important optical component, the diffraction grating has the capability to split and diffract incident white light beams into iridescent beams travelling in different directions. The emerging coloration is a form of structural coloration. In this paper, the non-isothermal precision glass molding is introduced for fast replication of periodic grating structures, which are employed to render iridescent colors on surfaces. Firstly, the effect of colorization and periodic grating profiles is theoretically analyzed. Secondly, different periodic micro gratings on silicon wafer, which are generally generated by photolithography, are employed in non-isothermal precision glass molding process as mold inserts. The molding result indicates that the periodic grating space and depth of grating structures can be precisely replicated from the mold inserts to polymer substrates. Subsequently, the split and iridescent color effects are demonstrated with monochromatic & white incident light beam and compared between samples with different periodic grating spaces. The optical effects of the replicated micro-structures confirm the feasibility of this method. The proposed non-isothermal precision glass molding process provides an alternative manufacturing option for realizing structural colors with large-volume and low-cost.