Exploring the effect of nanoparticle shape on the fluid flow characteristics of boehmite alumina nanofluid in a horizontal double-pipe minichannel heat exchanger is the goal of this study. The proposed boehmite alumina nanofluid could consist of dispersed cylindrical, brick, blade, platelet, and spherical shape nanoparticles in a mixture of water/ethylene glycol. In this study, the water and nanofluid pass through the annulus and tube side of the heat exchanger , respectively. To accurately simulate the behavior of nanofluid, the two phase mixture model is utilized in the simulation. In this investigation, the effect of different Reynolds numbers , nanoparticle concentrations and shapes versus important hydrothermal properties are investigated. The results show that, the spherical and platelet shape lead to the highest and lowest performance index of heat exchanger, respectively. Moreover, it is found that the rates of heat transfer, overall heat transfer coefficient , pressure drop, and pumping power increases with increase in Reynolds number and nanoparticle concentration, while the opposite trend is observed for performance index of the heat exchanger. For instance, at the Reynolds number of 20 000, by boosting the nanoparticle concentration from 0.5 to 2%, the performance index for nanofluid containing platelet shape and spherical shape nanoparticles reduces by 130.63 and 3.88%, respectively.