Triple-active-bridge(TAB) converter has excellent advantages in the applications of high power and high power density. Nevertheless, the power flows between each port of the converter are coupled and it results in the difficulty of control. The traditional proportional-integral(PI) controller for voltage control of the TAB has the disadvantages of relatively slow dynamic correspondence. In order to solve above problems, a model predictive control (MPC) strategy based on Newton-Raphson iterative method has been proposed in this work with good dynamic performance and high control flexibility to realize constant voltage control of ports, ports decoupling and voltage fluctuation suppression. Finally, the proposed model predictive control is compared with the existing decoupling control strategy by simulation, and the effectiveness of the proposed strategy is verified.