A door closure structure for a rotary door and a side-by-side refrigerator comprising the same are provided. The rotary door is rotatably mounted on a main body. The door closure structure comprises: a hinge assembly comprising a hinge body, a hinge plate and a hinge shaft, via which the rotary door is mounted on the main body; a supporting plate extended in a lateral direction, provided with a first hole and connected with a front end of the hinge body; a mask body fixed on the rotary door, in which a mask cavity is defined and in a surface of which a second hole is disposed; and an engaging block retractably and movably disposed in the mask cavity. A part of the engaging block is exposable out of the mask body from the second hole and engagable with the first hole to make the rotary door close the main body.