This paper manages with the modelling of quadruple junction solar cell (qjsc) constructed by using the semiconductor material of AlGaInP-GaAs-GaInAs-Ge at a particular value solar irradiance, temperature. Comparison of output I-V and P-V curve of the quadruple junction solar cell is done with triple junction cell made of semiconductor material InGaP-InGaAs-Ge and single junction solar cell (sjsc) made of a Ge semiconductor by using MATLAB/SIMULINK. It has been found a higher value of output voltage and power in quadruple junction solar cell as compared to single or triple junction solar cell. The above described quadruple junction solar cell is made by using the material having a same lattice structure which helps to ease the flow of current in all the four junctions and analysis is done at solar irradiance (1000-800-500) w/cm2. The whole analysis is done through pessimistic approach on the basis of the single exponential.