The cooling characteristic curves of the center, 1/2R and the border of the BT22 forged bars were measured. Results show there is a slow cooling stage in the 875 oC solution treatment cooling curve, due to the phase transformation. The curve exhibits one approximation flatform. The three positions have a big nonsynchronous characteristic of cooling. At the same time, microstructure development during the solution treatment cooling process at 875 and 810 oC was researched. According to the hardness test, non-uniform mechanical property of the medium forged bar after heat treatment was found.