Abstract: This gauge is based on the principle of the absorption of γ-ray by materials. Measuring the mass thickness is its basle function. Setting various sensors and computer softwares, it can be used to proceed inline measurement and control of d(?)nsity, consistency, interface between two phases, material level, mass flow and conveyance capacity of belt etc. Owing to the development of a new technique of peak stabilizing and micro-computer techniques, its index of precision, stability, reaction time etc. have achieved to a new level.