The combination of traditional learning where teacher and students are in same classroom and e-learning using technology is known as blended learning. This paper outlines the process of designing a blended learning on Differential Calculus. The Successive Approximation Model (SAM) is used as the instructional design upon the course. In the preparation phase, the information gathering is start to ensure an agreement between the learners need and learning solution.  Afterward, the design and prototype of blended course are implemented for Mathematics Education students' on Mathematics Department Universitas Negeri Surabaya. Along with iterative development phase the evaluation is conducted in order to make the course move to Alpha (a complete version of the instructional design blended learning) then evolve into Beta (a better version after Alpha revised) and then the Gold as finale version is reached.