Abstract: To meet the demands of the development of the AMPX formatted multi-group neutron-photon coupled constant library for the next generation nuclear power system, thorium molten salt reactor (TMSR), based on the evaluated nuclear data library, CENDL-TMSR recommended for the TMSR, and thermal scattering data sub-library and photon-atom interaction data sub-library of ENDF/B-Ⅶ.1, an AMPX formatted 238-neutron and 48-photon coupled multi-group constant library was developed using neutron-photon coupled group constant processing system NPLC-2. The library contains 400 nuclides and 12 thermal scattering materials, with five temperatures ranging from 300 K to 2 500 K. The library utilizes the narrow resonance approximation for the resonance self-shielding calculations. For some important actinium series nuclides, the Nordheim method was provided to perform the resonance self-shielding calculations. The preliminary critical and shielding benchmark verifications confirm the reliability of this new library.