Abstract: Impregnating pitch for graphite electrode is synthesized by air oxidation method using ethylene tar as raw material. The effects of oxidation temperature, oxidation time and air flow on the physicochemical properties of impregnating pitch were investigated, and compared with the coal tar-based impregnating pitch. The physicochemical properties of the obtained impregnating pitch were systematically characterized by laser desorption mass spectrometry, Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analysis and rotational rheometer. In the process of ethylene tar modification, the main factors that affect the physicochemical properties of the impregnating pitch are: oxidation temperature > air flow > oxidation time. A higher oxidation temperature is beneficial for the increase of the coking value of the obtained impregnating pitch. A lower air flow and a shorter oxidation time are conducive to reducing the softening point of the obtained impregnating pitch, which is favorable for the fluidity during the impregnation. Under the optimized preparation conditions with the oxidation temperature of 310 ℃, oxidation time of 4 h, and air flow of 0.2 L/min, the softening point and coking value of the obtained impregnating pitch are 93.44 ℃ and 46.73% (mass fraction), respectively. Moreover, there is a quinoline insoluble (QI) mass fraction of less than 0.1%, lower concentrations of S, N and O heteroatoms and better rheological properties, which is expected to achieve good impregnation effect.