A method of torque control and a torque control apparatus for a pneumatic torque tool are provided. The method includes: connecting a torque control apparatus between an air supply system and a pneumatic torque tool; under predetermined working and control conditions, driving the pneumatic torque tool at the first and second working air pressures to calibrate output torque, and to obtain maximum and minimum torque values; constructing correspondence curve between air pressure and torque value based on the first and second working air pressures and the maximum and minimum torque values obtained; entering any target torque value ranging from minimum torque value to maximum torque value of the correspondence curve to obtain a corresponding working air pressure value and drive the pneumatic torque tool; and verifying whether all working and control conditions are controlled within a predetermined range of variation to control the output torque.