ERP systems have been widely studied during the past decades, yet they often fail to deliver the intended benefits originally expected. One notable reason is the lack of understanding how the customization influence the ERP user acceptance when there is lack of system-to-business fit, which can lead to negative business outcomes. For some reasons, many have argued that a vanilla" implementation, i.e. without customization, is the "best" way to implement ERP systems. However, through quantitative research based on web survey, this dissertation revealed that, in China, customization is a must in ERP acceptance and project success. Because of the various risks in ERP project, financial, technical, functional and political, vendors and consultants are keen on helping the project manager to meet the budget and time target rather than to reap more benefit for business performance. Thus, customization usually had been avoided, and insufficient customization are more common than over customization. We proposed 15 hypothesis and 11 were supported, and the general conclusion that, customization level has significant positive influence on behavioral intention, the higher customization done, the higher behavioral intention (BI) to use the system. It is an instruction for companies that, right level of customization (CL) should be achieved instead of avoiding customization. And only higher strategic important customization should be included in the project when there is limitation in budget and time. We also confirmed that ease of customization is an important factor in selecting the right ERP solution. As a moderator, different role have different perception on customization, normal users have stronger expectancy in customization, so it is critical to explain to the users, which customization is strategic, and which one is for consistency purpose and could jeopardize the real benefit of ERP system. If it is not appropriate to do the customization in the project implementation phase, a plan for future system customization should be prepared and it will ultimately improve the system long term success.
