The utility model provides a centralizer of an oil tubular column of a horizontal well of an oil field. The centralizer is characterized in that an upper cone (6), a centralizing block (10) and a lower cone (12) are arranged among a central pipe (17), a pressure-bearing sleeve (3) and a centralizing sleeve (13). The centralizer is simple in structure, convenient in installation and reliable in use. When in use, the centralizer can enter into an upper end annular space of the upper cone (6) with a through hole at the upper part of the central pipe (17) by internally pressurizing the oil tubular column, is downwards pushed to lead the centralizing block (10) to be evenly expanded along the periphery, and supports that the oil tubular column can be positioned at the center of a sleeve, thereby guaranteeing that various underground tools such as a packer and the like can normally work.