Abstract: In order to solve a series of problems which are induced by unstable positioning, eccentric wear and fragile and easy-vibrating supporting spring of probe mechanism in the internal pipeline inspection with magnetic flux leakage and corrosion detector, a research on the probe mechanism of the detector is carried out, and a brand new one is developed and manufactured. The product has added auxiliary supporting spring and flexible joint hinges, and improved the defects of conventional probe mechanisms significantly. The detecting probe of the mechanism has transferred the previous structure from probe plus anti-wear layer to integral filling probe shell, and enhanced probe lift-off values and detection signal reliability. Compared with the conventional probe mechanism, the mechanism is applicable to effective improvement of detection data reliability and stability.