This paper reported 5 Dengue Fever (DF) cases were found among the 9 international travellers, who went to Malaysia, Burma from Nantong. In order to obtain the essential conditions, provide the international travellers with knowledge and preventive measures of DF, All of 9 travellers were surveyed by individual interviewing and blood—sample were detected for antibody. According to some epidemiological data, the area where the travellers went was epidemic area of DF, the time they arrived just in epidemic period. The results of individual interviewing showed that during they stayed abroad, they were bited by mosquito and contacted with a person who was suffering from illness, which similar with cold and other symptoms. Combinating the duration of DF with the date of onset, it was inferred that the 5 cases were infected with DF virus in the Burma. The same symptoms and signs of the 5 cases were as follows : the sudden onset with high fever, shivering, intense pains in the joints and muscles, poor appetite, nausea, vomiting and scarlet fever type of rash. Antibody of Dengue—3 were detected in all of the 5 cases, the highest titer was 1 : 10,240, the lowest titer was 1 : 2,560. In view the result of this investigation, authors put forward the following suggestions: (1) enhance the international travellers’ personal preventive consiousness to DF (eg: using mosquito expellant, and applying mosquito net). (2) If the imported cases were found, the isolation should be applied immediately and disinseeting, mosquito control measures also need be applied. (3) As the incidence of DF increased drastically in the most parts of the tropics and subtropics worldwide, especially in present decade, a total cases of DF were more than the total cases of the passed 25 years (1956—1980), meanwhile, considering the insect vectors of DF existed in the some areas in China, the population is susceptible to the DF, the vigilance of occur of DF in China should be caused. This paper reported 5 Dengue Fever (DF) cases were found among the 9 international travelers, who went to Malaysia, Burma from Nantong. In order to obtain the essential conditions, provide the international travelers with knowledge and preventive measures of DF, All of 9 travelers to surveyed by individual interviewing and blood-sample were detected for antibody. According to some epidemiological data, the area where the travelers went was epidemic area of ​​DF, the time arrived on in epidemic period. The results of individual interviewing showed that during They stayed abroad, they were bited by mosquito and contacted with a person who was suffering from illness, which similar with cold and other symptoms. it was inferred that the 5 cases were infected with DF virus in the Burma. The same symptoms and signs of the 5 cases were as follows: the sudden onset with high fever, shivering, intense pains in the joints and mu scles, poor appetiite, nausea, vomiting and scarlet fever type of rash. Antibody of Dengue-3 were detected in all of the 5 cases, the highest titer was 1: 10,240, the lowest titer was 1: 2,560. this investigation, authors put forward the following suggestions: (1) enhance the international travelers’ personal preventive consiousness to DF (eg: using mosquito expellant, and mosquito net). (2) If the imported cases were found, the isolation should be applied immediately and disinsept, mosquito control measures also need be applied. (3) As the incidence of DF increased drastically in the most parts of the tropics and subtropics worldwide, especially in present decade, a total cases of DF were more than the total cases of the passed 25 years (1956-1980), meanwhile, considering the insect vectors of DF existed in the some areas in China, the population is susceptible to the DF, the vigilance of caused of DF in China should be caused.