Abstract: In this paper, a physical model of inverted InGaP/GaAs/InGaAs triple-junction solar cell was established based on Poisson equation and carrier transport equation to ensure the reliability of inverted triple-junction cell under space radiation, and to reveal the effect of dislocation defects introduced by inverted process on the radiation attenuation of the cells. On the basis of ground equivalent experimental verification, the effect of radiation and internal dislocation defects on cell output were studied. Firstly, the relationship between the microscopic carrier recombination and the electrical performance of the cell was studied using the model. It is found that, when the fluence of 1 MeV electron reaches 10¹⁴ cm^-2, the non-radiative instead of radiative recombination of minority carriers dominates the degradation of the solar cells. In addition, the function relationship of the non-radiative minority carrier lifetime and electrical parameters with the threading dislocation density (TDD) of InGaAs bottom cells was simulated. It is found that, with the increase of TDD, the effect of radiation on the minority carrier lifetime decreases.