Process tailoring and verification are very important since project-specific processes are tailored from an organizational process standard and many quality assurance activities are based on the process standard. However, existing researches o not provide systematic method for the process tailoring and verification. In this paper, we propose a systematic method for formalizing a process standard clearly with the encapsulated reusable process modules, for tailoring process modules, an for verifying tailored process. AAG (Activity Artifact Graph) is used to represent and tailor each process module. Additionally, a prototype tool is implemented to support proposed method. We believe that proposed method is helpful in tailoring a process standard and verifying a tailored process.