The propagation of solitary wave in a one-dimensional composite granular chain with heavy and light particles by turns is investigated by using molecular dynamics simulation. Under the condition of larger or smaller mass ratio of light to heavy particles, scattering effect is weaker and both particle velocity and solitary wave velocity decay slowly. In the intermediate range of mass ratio, the scattering effect becomes stronger, resulting in a faster decay of particle velocity and solitary wave velocity. Moreover, effect of increasing velocity happens when teh solitary wave travels across the heavy-light interface, indicating that the solitary wave velocity is increased. Effect of increasing velocity is enhanced when the mass ratio of light to heavy particles decreases. Due to the combined action of scattering effect and the effect of increasing velocity, the traveling time of solitary waves can be modulated by altering the mass ratio of light to heavy particle.