The actual regenerative braking force of an integrated starter/generator (ISG), which is varied with desired braking deceleration and vehicle speed, is calculated based on an analysis of the required deceleration, maximum braking force of ISG, engine braking force and state of charge (SOC) of battery. Braking force distribution strategies are presented according to the actual regenerative braking force of ISG. To recover the vehicle’s kinetic energy maximally, braking shift rules for a mild hybrid electric vehicle (HEV) equipped with automatic manual transmission (AMT) are brought forward and effects of transmission ratios are considered. A test-bed is built up and regenerative braking tests are carried out. The results show that power recovered by the braking shift rules is more than that recovered by the normal braking control rules.