The invention relates to an oil gas well perforating bullet consistent in perforation diameter. The oil gas well perforating bullet is used for solving the technical problems that perforations formed in a casing pipe are different in size due to the fact that a perforator for a traditional perforating bullet is not centered in the perforating process of a cased well, and hence the hydraulic fracturing effect is not ideal. The oil gas well perforating bullet mainly comprises a cartridge shape cover, a shell body and high explosive. The cartridge shape cover is a metal cartridge shape cover. The inner surface and the outer surface of the cartridge shape cover are each formed by connecting an upper-section round face, a middle-section round face and a lower-section round face which are different in size and coaxial. The shell body is a metal shell body. The lower portion of an inner cavity of the shell body is cylindrical, and the middle and the upper portion of the inner cavity are in a truncated cone shape. The high explosive is composed of booster explosive and main charge explosive and located between the cartridge shape cover and the shell body. According to the oil gas well perforating bullet consistent in perforation diameter, perforations good in consistency can be formed in a casing pipe under the state that a perforator is not centered in the perforating operation process of a cased well, and the characteristics of being large in perforation diameter and deep in penetrability are achieved; and application and popularization of the oil gas well perforating bullet beneficially improve the hydraulic fracturing effect after perforating is conducted, so that the oil gas extraction efficiency is greatly improved, and the oil gas yield is increased.