The present invention relates to an adhesive composition, which comprises an epoxy resin; and a polyimide comprising a repeating unit. The repeating unit comprises a first repeating unit represented by formula (1) and a second repeating unit represented by formula (2): wherein X1, Y, Z, m, and n are as defined herein, the weight ratio of polyimide to the total amount of the epoxy resin is 50% to 100%, and in the epoxy resin, the proportion of the epoxy resin having a weight average molecular weight of less than 400 Da accounts for 12 to 40% by weight of the total amount of the epoxy resin. The adhesive formed by the adhesive composition of the present invention has a relatively high glass transition temperature.