Abstract: Multistate monotone coherent systems theory is a new development of system reliability theory. Up to now, the researches are all carried out under the hypothesis that the state sets of components and systems are totally ordered. These models have some limitations in practical applications. In this paper, a new mulristate monotone coherent system model has been defined according to actual systems monotone features, which is under the hypothesis that the state sets of components and systems are partially ordered. And some of its features, such as deterministic properties, stochastic performance and distribution class closure theorem: etc. have been discussed. Results are given.