The invention discloses a semi-automatic drying roller replacing device and a method thereof. A drying roller pushing-out mechanism, a drying roller running rack inner track assembly and a rack outerroller way assembly are matched with a crane to finish semi-automatic roller replacing work of a drying roller. According to the semi-automatic drying roller replacing device and the method thereof, in the whole roller replacing process, only when a drying roller enters a rack, manual assisting force is needed, the remaining operation is achieved wholly through hydraulic power, through semi automation, investment of manual physical power is reduced, during normal production, supporting wheels on turned-over tracks are used for axially fixing the drying rollers, due to rotation of the wheels, the lifting resistance of the drying rollers is greatly reduced, in addition, after the tracks are turned over, space on the transmission side of a rack is increased, and in the daily production and move, more comfort is achieved.