The utility model discloses a petroleum casing joint, and belongs to the field of petroleum and natural gas well drilling. The petroleum casing joint comprises a first casing end and a second casing end which are connected with each other, wherein the first casing end is provided with a coupling; a first section of internal threads and a second section of internal threads are arranged on the inner wall of the coupling, and a first section of external threads and a second section of external threads are arranged on the outer peripheral surface of the second casing end, wherein the first section of internal threads is connected with the first section of external threads, and the first section of internal threads and the first section of external threads are both API (American Petroleum Institute) knuckle threads; and the second section of internal threads is connected with the second section of external threads, and the second section of internal threads and the second section of external threads are both API buttress threads. The petroleum casing joint synthesizes good sealing performance of the knuckle threads with high tensile strength of the buttress threads, and guarantees connection strength and sealing reliability in nonconventional natural gas exploration and development.