As the disadvantages of cumbersome designing for the performance index function of the traditional zone model predictive control algorithm and steady state trajectories vary a lot after the controlled variable comes into the interval, a novel model predictive control algorithm is proposed based on interval characteristic and variable soft constraint. This algorithm only utilizes the desired output interval limits to construct the interval tracking bias term by an equivalent relation between the predictive output and the interval. The variable soft control term is constructed through the the quadratic form of increase of the prediction output controlled variable and operating variable, which contributes to reducing the range of steady-state track in the interval, then the above two are collectively referred to as zone tracking performance index based on variables soft constraint. The simulation experiment is carried out by taking the rotary kiln model as the controlled object, which validates the effectiveness of the proposed algorithm.