—Multiway Decision Graphs (MDGs) subsume Binary Decision Diagrams (BDDs) and extend them by a first-order formulae suitable for model checking of data path circuits. In this paper, we propose a reduction technique to improve MDGs model checking. We use a reduction platform based on combining MDGs together with the rewriting engine in the HOL theorem prover. The idea is to prune the transition relation of the circuits using pre-proved theorems and lemmas from the specification given at system level. Then, the actual proof of temporal MDG formulae will be achieved by the MDGs model checker. We support our reduction technique by experimental results executed on benchmark properties.