A study was conducted to examine the effect of ploydispersity on the phase behavior of block copolymer melts for two distinct distributions, such as equilibrium polymerization distribution (EPD)and Schulz-Zimm Distribution (SZD). The SZD was used primarily because of its simple functional form, which spans monodisperse distribution. It was observed that copolymer block melt acquired more parameters using SZD. This distribution impacts the phase behavior of copolymers with a polydisperse and monodisperse. It was found that some quantities effects of polydispersity were significantly altered when SZD was replaced by simulated equilibrium polymerization distribution (EPD) of the same polydispersity. The EPD possessed significantly more diblocks than SZD. The polydispersity indices perfectly matched a sizable difference in the degree to which the entropic elasticity of the polydisperse domain was affected and in the number of polymers that detached from the interface.