The online application service based on the new platform of cloud computing has been suggested as a major trend in information technology. Online office application is the most popular online service for individual users and it differs a lot with traditional stand-alone package. Based on innovation diffusion theory and technology acceptance model, this study investigated the influences of personal innovativeness and a variety of compatibility beliefs on using online office applications. The results indicate the value of innovativeness is a major cause and it brings both intrinsic and extrinsic motivations for using behaviour; conversely, the impact of perceived usefulness is insignificant. The results help us understand the early adopters of online office applications and the barriers for people to use this innovative service.