A numerical approach is proposed to design PID controllers for multivariable (multi‐input or multi‐output) systems. Different from traditional tuning methods, the PID parameters in the proposed method are determined by solving a nonlinear programming (NLP) problem. Since the objective function of the NLP problem is the traveling time between two states, the PID controller will drive the system from a given initial state to the desired final state in a quasi time‐optimal manner. The reason why the PID controller cannot generate truly time‐optimal movement will also be given. A seesaw system that has one input and two outputs will be used for simulation and practical implementation to illustrate the validity of the proposed method.