In the mid of January, 2010, the first Pandemic 2009 Influenza A(HIN1) (pHINI 2009) outbreak was occurred in outbreak in the village No 3, Pha Le commune, Thuy Nguyen district, Hai Phong city. With the application of descriptive-epidemiological and prospective study method, this study aimed to describe the epidemical development, and to identify the attract rate, transmission pattern of (pHINI 2009) in this outbreak. The results showed that in a community of nearly 1000 inhabitants, the outbreak was at a small scale, lasted for 13 days with a total of 9 clinical cases, among whom, 6 were confirmed by laboratory. There were 165 cases (among 727 blood samples collected) identified to have infection with the (pHINI 2009) virus. In this outbreak, the clinical attack rate was very low (0.9 percent [0.55 percent - 1.97 percent]) while the infection rate was rather high (22.7 percent [19.7 percent - 25.9 percent]). The infection rate of Pandemic 2009 Influenza A(HIN1) virus differed by age structure and occupational pattern. The attack rate was highest in the group from 5 to 14 years old and the older groups got the higher rate of infection. Similarly, the pupil group was also suffered the highest attract rate (40.82 percent [(33.4 percent - 48.5 percent]). This findings will provide scientific evidence for decision makers to develop an effective epidemic controlling strategy for coming influenza 'pandemic that we have to face in the future.