A propylene production process is disclosed. The process comprises (a) reacting a feed stream comprising isobutene in the presence of a skeletal isomerization catalyst to obtain an isomerized stream comprising C4 olefins; and (b) reacting the isomerized stream with ethylene in the presence of a metathesis catalyst to form a metathesis product stream comprising propylene, C4 olefins, and C5+ olefins. The metathesis reaction pressure is equal to or lower than that of the skeletal isomerization.