The droplet deformation's mechanism in a simple shear flow is well understood, but most studies only considered a uniform temperature field of immiscible droplet systems. This research investigates the possible droplet deformation and visualizes its evolution under selective radiation heating, which is a novel method to modify droplet dispersion via thermo‐physical mechanism. Polybutenes and PDMS silicone oils were employed as the dispersed droplet phase and matrix phase, respectively. Results showed that the mean value of the droplet's modified deformation parameter was limited to 0.12 and 0.08 at an isothermal ambient room temperature having a viscosity ratio of 4.32 and 17.69, respectively. The droplet under selective radiation was visualized. Experimental investigation showed that the selective radiation method enhanced the droplet deformation, as confirmed by the obtained droplet image during laser irradiation process, even allowing droplet breakup. At a moderate level of viscosity ratio (4.32), selective radiation can be applied effectively, whereas at a higher level of viscosity ratio (17.69), droplet elongation‐breakup and droplet retraction were observed. A novel method to improve droplet deformation and dispersion was studied in this work. The method was carried out by providing an external heat source, infrared laser irradiation, to the microdroplets of an immiscible system or blend. Different heat absorption will form temperature disparity in the droplet and matrix phase. The temperature disparity will then realize into a viscosity ratio modification of the immiscible blend.The droplet dispersion enhancement is independently and immediately achieved from outside the system through this viscosity modification.