The invention discloses an oedaleus asiaticus protein tyrosine phosphatase PTPN4 as well as an encoding gene and application thereof. At first, the oedaleus asiaticus protein tyrosine phosphatase PTPN4 is cloned from oedaleus asiaticus, a primer is designed for the oedaleus asiaticus protein tyrosine phosphatase PTPN4, and dsRNA used for interfering with the oedaleus asiaticus protein tyrosine phosphatase PTPN4 is synthesized, and is introduced in the oedaleus asiaticus by an injection method to perform RNAi on the oedaleus asiaticus protein tyrosine phosphatase PTPN4. The result shows that after the dsRNA is injected into the oedaleus asiaticus, the growth rate and the weight grain are remarkably improved, and the oedaleus asiaticus protein tyrosine phosphatase PTPN4 plays an important role in the insect growth and development process. A new method is provided for regulation and control of injurious insect molecules, and a theoretical basis is provided for deeply understanding an insect growth and development mechanism and creating a new biopesticide preparation.