Ball mill coal pulverized system is a multivariable system with great inertia and strong coupling, and its dynamic performance changes with working conditions. So according to these features, using general PID control can not match well. Under this condition, a new decoupling PID control strategy is proposed, which appended decoupling compensator in the PID loop. The simulation experiment shows that the proposed method resolved the problem of variable coupling effectively and got a perfect control result.