The utility model discloses a high-temperature closed dehydration test bottle for an ultra-thick crude oil emulsion. Two sections of tubular bottles with different diameters are connected into a whole so that tube cavities of the two sections of tubular bottles are mutually communicated to form a bottle cavity of a combined bottle body; an outer bottle wall of the combined bottle body is provided with scales; a round bottle opening is provided with an annular body surrounding the round bottle opening; a clamp hoop arranged at the bottom side of an annular seat body placed on the annular body is matched with and closely buckled on the annular body; the radius of a round gasket arranged in a through hole formed by the annular seat body is larger than the radius of the round bottle opening; an edge part of the round gasket is in face contact with a plane at the top side of the annular body main body; a round press piece is arranged between a bolt and the round gasket and is positioned into the through hole; the bolt is arranged on the annular seat body in terms of threaded connection fastening force to push against the round gasket through the round press piece indirectly; moreover, the edge part of the round gasket is in press contact with the plane arranged at the top side of the annular body main body so that the round bottle opening is sealed by the round gasket. Requirements for thermochemical dehydration of a high-adhesion ultra-thick crude oil sample can be met.