In this paper, the transmission characteristics of saliva droplets expelled when coughing are examined to evaluate the cough-induced droplet infection of SARS. Three subject experiments were performed, with the results indicating that there are about 6.7 mg of saliva droplets expelled at speeds of up to 22 m/s per cough, and the droplets can travel more than 2 m. In addition, the transmission processes of coughed saliva droplets of different diameters were analyzed. The results indicate that droplet infection is liable to occur when in close contact with SARS patients through coughed saliva droplets.