Abstract: The invention provides a thermal structure coupling analysis method of a solid rocket motor nozzle considering the structural gaps, comprising S1: establish a model of flow field in nozzle and ascertain the cross-sectional area at different positions along the axis, perform quasi-one-dimensional isentropic flow analysis of the nozzle flow field by Newton iteration method; S2: use Bartz formula to ascertain the boundary of the nozzle convective heat transfer coefficient; S3: establish a numerical analysis project of nozzle thermal structure; a two-dimensional axisymmetric model of the nozzle thermal protection structure and a material model thereof; S4: proceed a numerical analysis of the nozzle thermal protection structure heat transfer, including model setting, material setting, contact setting, meshing, solution parameter setting, boundary condition setting, solution and result post-processing; S5: proceed a numerical analysis of the nozzle thermal protection structure thermal stress, including solution par