Abstract: The outbreaks of type O footandmouth disease (FMD) severely affect development of Chinese hog industry, its causative agent is type O footandmouth disease virus (FMDV), which has been evolved several lineages. The available FMD vaccines in China cannot afford sufficient protection against viruses of multilineages, which exert important obstacle to disease control. In order to develop vaccine candidate with characteristics of good immunogenicity and broad spectrotype, we constructed a fulllength cDNA clone with genetically modified in capsid protein VP3 (58 amino acid) and VP1 (43, 48, 137, 139, 140, 141, 142 amino acid) based on the infectious cDNA clone of O/HN/93 vaccine strain. Upon cotransfection of BHK21 cells with linearized recombinant plasmids and plasmids expressing T7 RNA polymerase, the virus was rescued. The results of RTPCR and sulk mice pathogenicity showed that the rescued virus could be stably maintained during serial passages and has similar pathogenicity with parental virus for sulk mice. To test if the genetically modified virus can be used as a vaccine candidate, the pigs inoculated with inactivated FMD vaccine which made from rVOSyNa and O/HN/93 viruses were challenged with swineisolated strains of Chathay, PanAsia and Mya98 topotypes, respectively. As a result, the rVOSyNa vaccinated pigs were fully protected against three viruses challenge after 28 days postvaccination, in contrast, 16/16 O/HN/93 vaccinated animals fully protected against viruses of PanAsia and Mya98 topotypes challenge, but only 12 /16 O/HN/93 vaccinated animals got protection from virus of Chathay challenge. Our results demonstrated that genetically engineered FMDV is a good vaccine candidate with improving protection against virus of Chathay topotype challenge and expanding spectrotype.