United mathematical models for four reactors, two microporous inert membrane reactors as O-2 (MR-O) or H-2 (MR-H) distributor and two traditional reactors (i.e., three-stage reactor (TSR) and packed-bed reactor (PBR)) with different feeding strategies, are developed to describe direct propylene epoxidation with H-2 and O-2 to produce propylene oxide (PO). Effects of the feeding strategies on reactor performances (i.e., C3H6 conversion, PO selectivity, PO yield and H-2 efficiency) are studied under both isothermal and non-isothermal conditions by using gPROMS. Significantly different reactor performances along the catalyst length are observed and then explained by the reactants and products concentration profiles and/or the temperature distributions. Then, effects of the catalyst lengths of the four reactors are further investigated. It is found that the MR-O gives rise to the outlet C3H6 conversion of 11.3%, which exceeds the previously estimated value (i.e., 10%) with a commercial potential. Finally, an attempt is made to probe whether increasing the H-2 and C3H6 feed concentrations in the MR-O without the explosion risk further improves the reactor performance. All the results indicate the potential of the MR-O for the commercial production of PO by direct propylene epoxidation with H-2 and O-2.