Viral diarrhea is a great threat to children's health in developing countries. We conducted a prospective surveillance study of acute diarrhea of young children at Tianjin Children's Hospital from April 2008 to April 2009. Viral infections were detected in 356 of the total 766 collected stool specimens (46.48%). Rotavirus infections were the most common (27.94%; predominant type G1), followed by adenovirus infections (17.62%; predominant type Ad41), norovirus infections (5.87%; predominant type GII-4/2006 b), and astrovirus infections (3.15%; only HAstV-1). Children younger than 1 year old were the most susceptible population to viral infections (87.9%). Diarrhea, vomiting, and fever were the most frequent clinical symptoms among the infected patients. The viral infections had no age, sex, or regional differences. Most infection rates were higher in the autumn, winter, and spring. This study supported that the rotavirus vaccine should be included in the Expanded Programme on Immunization in China.