The invention discloses a warming-free solar greenhouse used in a cold region and a construction method thereof. The warming-free solar greenhouse comprises a rammed earth wall forming a main body frame of the solar greenhouse through enclosure, a foaming cement layer arranged on the outer side of the rammed earth wall, a heat insulation layer arranged on the inner side of the rammed earth wall, keels erected at the upper portion of the main body frame composed of the rammed earth wall, and a heat insulation layer, wherein the keels comprise frameworks and cross beams, the cross beams includetop beams and front end beams, the top beams are arranged at the top of the main body frame, and the front end beams are parallel to the top beams and are arranged on the front-end wall body of the main body frame; the frameworks include first frameworks and second frameworks, the first frameworks and the second frameworks are symmetrically arranged on two sides of the top beams, the first frameworks are slidingly connected with the front end beams, the tops and the bottoms of the first frameworks are both provided with clamping grooves, cover plates are laid on the second frameworks, solar cell panels are laid on the cover plates, the bottoms of the cover plates are provided with sealing plates, and the rear ends of the sealing plates are provided with extending portions. The constructionmethod is simple in construction process and efficient, energy is saved, the price is low, the service life of the greenhouse is long, and a heat storage function is good.