The utility model discloses a wheel type thickness measuring probe for a pipeline detector, which is designed for accurately detecting the wall thickness of a pipeline. A thickness measuring wheel, a supporting wheel, a slip ring base and an end cover of the thickness measuring probe are connected to supporting arms connected with a detector frame through a shaft and operate in the pipeline along with the detector; the slip ring base is fixed in the end cover and rotates along with the thickness measuring wheel and the supporting wheel, a slip ring is fixed in the slip ring base and tightly contacted with a carbon brush device; the thickness measuring wheel is internally provided with an ultrasonic probe which is used for realizing sound filed coupling between the ultrasonic probe and the pipe wall; and a metal block is embedded in the supporting wheel and operates together with a proximity switch arranged on the supporting arm so as to excite generation of ultrasonic signals. The probe disclosed by the utility model is suitable for being used on detectors for detecting pipeline deformation, corrosion and cracks, and the length of the supporting arm can be adjusted, thereby being convenient for integration of the detector and applicable to detection of pipelines with different apertures, and ensuring detection signals to be accurate, continuous and stable. The wheel type thickness measuring probe for the pipeline detector has the advantages of good supporting performance, strong adaptability, impact resistance and wear resistance, and long service life.