The objective of the present work is to examine evaporation cooling of water droplet due to surface roughness of impinging surface with droplet diameter under conductive heat input condition. The surface temperatures varied from 80 to $55^{circ}C$, surface roughness ($R_a$) was from 0.12 to $1.14{mu}m$ and droplet diameter was from 2.4 to 3.0 mm. The results show that the total evaporation time is shorter for the smaller droplet size, the time averaged heat flux has maximum value for the smaller droplet size. The variations of contact angle and the variations of volume increase for the larger droplet size.