To improve the quality of the light guide plate (LGP) made by injection molding, a fabrication method based on hot embossing was proposed. The silicon mold of the LGP with micro pyramid array was fabricated by wet chemical etching. The experiments of embossing the LGP were performed with a self-designed hot embossing machine. Orthogonal method was used to analyze the imprint pressure, the holding time, the imprint temperature and the width of pyramid with respect to the accuracy of replication (AOR). The experimental results show that the imprint temperature has the greatest effect on the AOR, followed by the imprint pressure and the holding time, while the width of micro pyramid has the minimal effect on the AOR. The increase of imprint temperature can obviously improve the pattern filling quality in the lower imprint pressure (0.7MPa). At last the optimal process parameters were obtained with the imprint pressure of 0.9MPa, the holding time of 5min and the imprint temperature of 130°C.