The invention relates to semi-automatic flaw detection equipment suitable for locomotive wheel set detection. The semi-automatic flaw detection equipment comprises a detection trolley, a lifting platform, a top runner mechanism, a probe carrier propelling mechanism, a probe carrier and equipment accessories. The semi-automatic flaw detection equipment is characterized in that the detection trolley moves along a rail in a trench, the lifting platform is mounted on the detection trolley through a guide column, the top runner mechanism is fixed on the lifting platform, the probe carrier propelling mechanism is fixed on the outer side of a force bearing arm of the top runner mechanism, and the probe carrier is mounted on the probe carrier propelling mechanism by means of quick inserting. During working, the semi-automatic flaw detection equipment is positioned below the bottom of a train, four probe carrier propelling mechanisms are arranged on two sides of one wheel set, and detection positions can be selected flexibly and freely according to underbody space of a locomotive.