Method for degradating thermosetting resin, catalyst composition used therein and resin composition obtained thereby

A degradation method of thermosetting resin is provided. The method includes the following steps, for example, a first resin composition is provided. The resin in the first resin composition includes a carbon-nitrogen bond, an ether bond, an ester bond or a combination thereof. The first resin composition and a catalyst composition are mixed to perform a degradation reaction to form a second resin composition. The catalyst composition includes a transition metal compound and a group IIIA metal compound. The second resin composition includes a resin monomer or an oligomer thereof having functional groups. The functional group includes an amine group, a hydroxyl group, an ester group, an acid group or a combination thereof. A catalyst composition used in the degradation method and a resin composition obtained by the degradation method are also provided.