The invention discloses a glass substrate loading and unloading method in vacuum coating. The glass substrate loading and unloading method includes the steps of a, setting a rotary base at the bottom of a substrate support to allow the substrate support to horizontally freely rotate on the rotary base; b, loading a front-side glass substrate onto the front side the substrate support, then rotating the substrate support 180 degrees on the rotary base, and loading a reverse-side glass substrate onto the reserve side of the substrate support; c, using a double-side magnetron sputtering coating machine to performing front-side and reserve-side coating; d, rotating and conveying the substrate support after the coating to a substrate loading and unloading area, unloading the glass substrate on the front side of the substrate support, rotating the substrate support 180 degrees on the rotary base, and unloading the glass substrate on the reverse side of the substrate support; repeating the steps b-d to achieve glass substrate loading and unloading in the vacuum coating process. The glass substrate loading and unloading method has the advantages that glass substrate loading and unloading on the reverse side of the substrate can be performed by one operator, the operator does not need to walk to the back side of the substrate support, manpower is saved while glass substrate loading and unloading speed is guaranteed, and labor intensity can be lowered.