Magnesium alloy pipe sectional reducing equipment comprises a lathe, a chuck, a slide carriage box and a clamp, and is characterized by further comprising a sectional reducing sleeve and an auxiliaryclamp; Wherein the segmented reducing sleeve comprises a horn mouth, a reducing inner cavity, a secondary horn mouth and a secondary reducing inner cavity, the horn mouth is communicated with the reducing inner cavity, the opening of the horn mouth is gradually reduced towards the direction of the reducing inner cavity until the diameter of the horn mouth is the same as that of the reducing innercavity, and the reducing inner cavity is a cylindrical inner cavity; The diameter-variable inner cavity is communicated with the secondary horn mouth, and the diameter of the diameter-variable inner cavity is the same as that of the opening of the secondary horn mouth; And the secondary horn mouth is communicated with the secondary reducing inner cavity, an opening of the secondary horn mouth is gradually reduced towards the direction of the secondary reducing inner cavity until the diameter of the opening of the secondary horn mouth is the same as that of the secondary reducing inner cavity,and the secondary reducing inner cavity is a cylindrical inner cavity.