Abstract: In this study, the Escherichia coli strain contains the gene encoding Taq DNA Polymerase was shaking-cultured in constant temperature incubator shaker at 37℃ for synthesizing of the Polymerase, using IPTG as an inducer.The enzyme was then precipitated by 40% ammonium sulfate.Taq DNA Polymerase obtained in this way was negatively charged, and anion-exchange column was used to purify the protein. It was found that this performance can remove the unneeded small biological molecules more quickly than the traditional method of dialysis; meanwhile, it not only keeps biological activities of Taq DNA Polymerase, but also shortens time of purification and improves pure degree of Taq DNA Polymerase. The rice cDNA,rice genomic DNA and soil microorganism DNA were used as template to PCR amplification and the PCR products were sequenced. The results showed that the polymerase had great activity and fidelity.