Embodiments of the disclosed technology disclose a method for fixing glass substrates and a method for preparing a flexible display device. The method for fixing glass substrates comprises coating an edge portion of a first glass substrate corresponding to a second glass substrate with epoxy resin and screeding the coated epoxy resin layer, adhering the second glass substrate to the first glass substrate, and annealing the two glass substrates. With the technical solution of this disclosed technology, the time period for fixing the adhered glass substrates can be reduced with an improved productivity.