The utility model discloses a reflection prism device used for laser transit survey. A reflection prism is attached on the surface of a magnetic block or a magnetic sheet; the reflection prism is arranged in the magnetic block which is processed precisely; when measuring the front surface, the bottom surface of the magnetic block is used for being absorbed on the measuring surface; and when measuring the side surface, the side surface of the magnetic block is used for absorbing. The device can better use the existing prism manufacture technology, can be fixed conveniently, has high efficiency and can better guarantee the measurement precision.