This paper presents a technique for optimal tuning of continuous time PID controller for bilinear MIMO plant with piecewise constant input signals. The proposed technique is based on minimization of quadratic proximity criterion applied for transient processes of open-loop control system and its implicit reference model (internal model control). The tuning algorithm for controller parameters uses estimates of bilinear MIMO plant parameters. The algorithm of parametric identification is used for determining the bilinear plant parameters. The PID controller optimal tuning algorithm for bilinear continuous time MIMO system is presented. A numerical example of two-channel bilinear MIMO plant control using two-channel PI controller is considered. It shows good controller performance within given range of coordinate and parametric disturbance.