The Engineering Materials Diffractometer Application Kit called EMAKi has been developed to control the Engineering Materials Diffractometer, TAKUMI, and treat data obtained by it. It is expected that TAKUMI will be widely used by not only academic users but also industrial users. We have designed EMAKi to be user-friendly interface for novice users by graphical user interface (GUI). In addition, adopting Python programming language for its development has enabled advanced users to control the diffractometer flexibly and treat the data easily. During instrumentation commissioning and running user programs, the software has demonstrated useful.