Structured Object-Oriented Formal Language (SOFL) is a representative formal engineering method for software development. It offers a three-step specification approachtoconstructingformalspecifications,andspecification-based inspection and testing for verification and validation. In this paper, we describe a novel approach to applying the SOFL method to achieve agile development process. This approach results from our experience in several collaboration projects with industry, and aims to strike a balance between the fast delivery of software product and the assurance of its quality. We have tested the approach in developing a prototype test support tool. Keywords Formal engineering methods · SOFL · Agile process · Semi-formal specification