The invention discloses an adjustable oral cavity orthodontics mouth prop, and particularly relates to the field of a mouth prop. The adjustable oral cavity orthodontics mouth prop comprises a supportring, wherein the support ring comprises two groups of opposite side connecting rings, two groups of opposite bottom connecting rings and a top connecting ring, wherein the two groups of the bottom connecting rings are fixedly arranged at one ends away from the top connecting ring, for the two groups of the side connecting rings, the top connecting ring is fixedly arranged at the top between thetwo groups of the side connecting rings, openings are formed in opposite sides of the two groups of the side connecting rings, an elastic sheet is fixedly arranged in each opening, and multiple groupsof the elastic sheets are arranged in the directions of the openings; and a penetrating hole is arranged in each elastic sheet, a flexible strip penetrates through the inner part of each penetratinghole, and two ends of each elastic strip are respectively and fixedly arranged at two ends of the inner part of each opening. The side connecting rings, the bottom connecting rings and an adjustment seat are arranged, so that the expanding degree can be adjusted according to the size of mouths of different patients, the bending deformation effect is good, the bending part is durable and not liableto crack, and the operation is simple and convenient.