A large-scale dengue fever (DF) outbreak occurred in Chaozhou, Guangdong province, China 2015. In our study, 528 dengue-positive patient samples were collected for clinical and laboratory data analysis. 491 cases (93.0%) were primary dengue fever (PDF), 22 cases (4.2%) were dengue hemorrhagic fever (DHF) and 15 cases (2.8%) were diagnosed with severe dengue fever (SDF). All cases were infected by dengue virus serotype 2 (DENV-2), and the isolated strains belonged to cosmopolitan genotype, which were grouped closely with Malaysia strains from 2010 to 2014. Moreover, the study showed that laboratory indices have significantly difference in PDF, DHF and SDF patients. A comprehensive analysis of these data could assist and guide the clinical diagnosis for DF, which has an important significance for the control of dengue virus infection.