A study of defects in silicon produced by hightemperature electron irradiation was carried out. It was found that the introduction rate of defect increased with the temperature at which the samples were irradiated by electron. After the temperature reached an "extreme" value Tm, the introduction rate of defect began to decrease. The Tm value was related to the annealing activation energy of defect. It was also found that the density of E3 (Ec-0.36 eV) defects greatly increased in hightemperature electron irradiation. When electron irradiation was carried out at 330℃, the density of E3 defects was about 6 times as large as that at room temperature. The possible structure of the E3 defect is multivacancy-oxygen complex.