Background: On October 15, 2006, the China information system for disease control and prevention revealed typhoid fever (TF) cases increasing greatly from October 7, comparing with the same period of the previous year, in a coastal city, P.R. China.Objective: To identify its epidemiological cause, and develop its control measures.Methods: TF case was defined as any case involving onset of fever between October 7 and December 15, 2006, plus the following: high fever (>38.5 • C), headache, malaise, intestinal hemorrhaging, myalqia, or rose-colored spots on the skin, and with the laboratory result of the decreasing Eosinophil cell or Widal test (+) in Jiaojiang district. The first 25 cases from October 7 and 100 controls randomly chosen from neighborhood of each case, age referring to +5 year old, were selected to carry out a case-control study, through questionnaire. Well water was randomly selected to detect the total bacteria, Coliform group. The chi-square test and non-conditional logistic regression analysis was used for statistical analysis. Statistical significance was assessed by the two-sided test with the test level equaling 0.05.Results: Totally 58 typhoid cases, including 29 confirmed and 29 probable cases were identified between October 7 and December 15, 2006. The cases were mainly non-residents. Through non-conditional logistic regression analysis, the result showed that mode to use well water (Odds Ratio [OR] = 5.71, 95%. Confidence interval [95% CI] = 2.23-14.59) and eat outside (OR = 8.18, 95% CI = 1.51-44.26, AR = 0.27) was the main causation of this outbreak. In addition, through chi-square test, the result also shows that Xiama market (OR = 5.46, 95% CI = 1.61-20.37, AR = 0.23), cooked food taking (OR = 4.13, 95% CI = 1.44-11.92, AR = 0.27 may also the suspected risk factors of this outbreak. The number of total bacteria and Coliform group in well water both far outnumber the national drinking water standards. Further more, through field investigation, a public toilet was found 5 meters far from a well in the Xiama market.Conclusion: This TF outbreak was mainly caused by the inappropriate manner to use contaminated well water system, probably by septic tank seepage into storage well and unhealthy food habits. The epidemic was controlled by the effective measures.