TIANSeq HiFi Amplification Mix is a new high fidelity PCR amplification premix, which is suitable for PCR amplification of high-throughput sequencing library and other PCR related cloning and detection. The Ultra HiFi DNA Polymerase in the pre-mixed solution is a new type of fast and high fidelity DNA polymerase developed by directed molecular evolution technology, which enhances the affinity of DNA polymerase to templates. This enzyme has improved amplification speed and extension ability, and success rate of PCR and products yield is increased. The enzyme also has excellent 3'- 5' exonuclease activity (Proofreading activity), and its fidelity can reach the level of mainstream products in the market, with the authenticity in the process of gene and library amplification ensured. In addition, the DNA polymerase in the product has a HotStart function, which can effectively control non-specific amplification and enzyme activity loss under low temperature, thus ensuring specificity and stability of PCR amplification. A PCR reaction enhancement system is also integrated in the Mix, which not only improves the stability of the Mix, enhances the tolerance of polymerase to PCR reaction inhibitors, but also improves the adaptability of Ultra HiFi DNA Polymerase to templates with different GC contents, so that the product has wide sample universality and sample input range, and minimizes the base preference of PCR reaction.