This invention discloses an olefin oxidation process, including a step of under olefin oxidation conditions, successively passing a reaction feed from the No.1 catalyst bed through the No.n catalyst bed, wherein if the apparent velocity of each of the reaction materials passing from the No.1 catalyst bed through the No.n catalyst bed is respectively named as v1 to vn, and if m represents any integer in the region [2, n], the relationship vm-1