Abstract: The gear disk milling tool based on the forming principle is the necessary tool for producing large-scale wind power transmission gears. However, due to the influence of the machining principle error, the traditional gear milling tool can only process specific types of gears, and the versatility of the cutter is poor. The traditional tool profile cannot guarantee the machining accuracy and service life of the gear to be machined, and cannot maximize the principle advantages of form milling. In this paper, the mathematical model of the actual profile curve of the gear involute is established. Based on the relative motion track of the top angle of the conjugate rack, the equation of the tooth root transition curve is established. According to the relative position of the tooth root transition arc space, the design methods of different forms of tooth profile curves are reconstructed. Based on the inverse projection method, the numerical model of the blade edge curve is established with the parameters of the gear to be machined as variables. According to the principle of the blade space envelope, the design method of the profile curve of the indexable gear disk milling cutter is reconstructed. The numerical analysis of gear tooth profile and blade profile curve is carried out, and the main forms of large wind power transmission gear tooth profile curve and indexable gear disk milling tool edge profile curve are studied.