Multijunction tandem solar cells from compound materials are highly attractive for higher cell efficiency need to be applied in space applications. In this work, numerical simulations were conducted with novel promising InGaN compound material by utilizing AMPS simulator to explore the possibility of higher efficiency of the multi-junction tandem solar cell. This simulation was done with the different ratio of In and Ga content to investigate the optimum band gap combinations of tandem solar cells, and it has been found that the maximum conversion efficiency of the triple junction tandem solar cell is 42.34% (Voc =1.33V, Jsc=36.15mA/cm2, and FF =0.88) with this InGaN compound material. Finally, the stability of the designed cell has been investigated and found that the temperature coefficient (TC) of the proposed cell is −0.04%/°C which indicates the higher stability of the cell in stressed condition.