In this study a few galaxies are considered as samples from the atlas of spiral galaxies for estimating the acceleration constant a 0 of Modified Newtonian dynamics (MOND). Considering the model of flat disk galaxy, the values of disk acceleration due to gravity ( g disk ) are obtained which is equivalent to Newtonian gravity ( g N ). This is further helpful in determining a 0 through modified Newtonian dynamics. The values obtained are 0.069–1.78 ( × 10 - 13 km / s 2 ) . Out of which 0.7–1.33 ( × 10 - 13 km / s 2 ) are in a good agreement with the observed values. The MOND induced rotation curves of the galaxies are studied for the following interpolating functions: μ x = x ( 1 + x 2 ) - 1 2 , μ x = x 1 + x and μ x = 1 - e - x . This modification yields flat rotation curves. These curves are analyzed and compared with observational data. The simple interpolating function μ x = x 1 + x is found to be a better fit to MOND. Also, the relation between acceleration constant and the surface mass density have been obtained and it is observed that acceleration constant increases with increase of surface mass density.