As an essential part of the downhole assembly for coiled tube drilling, the diverter limits the development of coiled tube drilling technology. In this paper, an electric drive steering gear for coiled tube drilling was designed to solve the problems of long steering cycle and low precision of the existing hydraulic steering system. According to the actual drilling site of the steering gear and the requirements of the downhole drilling tool assembly, the main technical parameters and overall scheme of the steering gear are determined, and the theoretical calculation of the driving motor and reducer is completed. Numerical simulation of key components of steering gear, mechanical analysis of external joints, reliability verification of electronic cabin and transmission crankshaft, and flow field analysis of flow channel structure to determine optimal flow channel structure are required. The results show that the optimized outer joint under the action of external force; both electronic cabin and the transmission crankshaft meet the strength requirements, and the lowest natural frequency of the transmission crankshaft does not resonate with the natural frequency of the equipment. The steering gear has a reasonable design structure, reliable strength, and meets actual engineering application requirements.