Reachability probabilities and expected rewards are two important classes of properties that are used in probabilistic model checking. Iterative numerical methods are applied to compute the underlying properties. To guarantee soundness of the computed results, the interval iteration method is used. This method utilizes two vectors as the upper-bound and lower-bound of values and uses the standard value iteration method to update the values of these vectors. In this paper, we use a combination of value iteration and policy iteration to update these values. We use policy iteration to update the values of the lower bound vector. For the upper-bound vector, we use a modified version of value iteration that marks useless actions to disregard them for the remainder of the computations. Our proposed approach brings an opportunity to apply some advanced techniques to reduce the running time of the computations for the interval iteration method. We consider a set of standard case studies and the experimental results show that in most cases, our proposed technique reduces the running time of computations.