Abstract: In order to explore the tensile mechanical behavior of a new high temperature resistant resin, polyethersulfone ketones with diazanone structure ("PPESK"), a comparative experiment was conducted in this paper, and a typical commercial resin, polyetheretherketone ("PEEK"), was used as a reference. The special mechanical behavior of PPESK was analyzed in detail from three aspects: Heat resistance, sensitivity of tensile property to the change of tensile rate, and tensile deformation to fracture behavior. It is shown that the heat resistance of PPESK is much better than that of PEEK, and the strength and modulus are more sensitive to tensile rate changes. At room temperature up to 250℃, the deformation is within 6%, and brittle fracture occurs; Only when the temperature reaches 260℃ and above, PPESK shows large deformation and toughness fracture occurs, which is very different from PEEK, which produces large deformation and toughness fracture under various conditions. The generation of the above special mechanical behavior is related to the twisted, non-coplanar heteronaphthalene ring in the structure of PPESK, as well as the strongly polar sulfone group and carbonyl group. These groups make PPESK amorphous form, and the molecular chain rigidity increases, the intermolecular forces increase, which in turn causes the glass transition temperature increases, the molecular movement ability decreases, resulting in more heat-resistant PPESK, tensile properties of more sensitive to changes in tensile rate, the form of fracture to the brittle fracture accompanied by the breakage of the main chain is dominant.