The thermal environment of maneuvering rudder shaft is a local problem to be considered in the design of thermal protection system of hypersonic missile. The flow structure in rudder shaft gap is complex， and under typical flight conditions， the peak of the local thermal environment of the rudder shaft is more serious than that of in large area. Aiming at the problem of thermal environment of hypersonic maneuvering warhead shaft， combined with numerical calculation and wind tunnel test， the variation of thermal environment of rudder shaft with attack angle， rudder deflection angle and Mach number is studied. Then， a four-parameter interpolation fitting method suitable for predicting the peak heat flow of rudder shaft is established. The results show that， for the rudder like letter “+”，the thermal environment of horizontal rudder shaft is the most severe； under the condition of small attack angle， the dimensionless heat flow of the rudder shaft increases gradually with the increase of the rudder deflection angle and Mach number， but under the condition of large attack angle， the influence of Mach number and rudder deflection on the dimensionless heat flow of the rudder shaft is small. The four-parameter fitting method established in this paper can be used to rapidly evaluate the peak thermal environment of the rudder shaft along the trajectory.