Abstract: Robot is the most advanced method for the quantitative in-service inspection of tank floor at present. In China, however, there is no such robot equipment to satisfy the needs of intelligent pipeline development in the future. For the research and development of Chinese first tank bottom in-service inspection robot, the development status of this technology was analyzed in this paper. In addition, its design considerations and functional implementation scheme were proposed according to the characteristics and inspection requirements of storage tanks in China. It is shown that mechanical structure design, implementation scheme of key functional units, explosion-proof design and necessary auxiliary design are important aspects of robot development. The mechanical structure design mainly focuses on the factors of dimension, weight, driving method, sensor mounting mechanism, cable gravity balance, materials and debris layer processing. The robot determines its position and direction based on the principle of time difference of sound wave, and inspects the defects by means of the immersion ultrasonic technology. The adoption of the combined explosion-proof measures can increase the robot's equipment protection level to Gb so as to meet most applications. The design scheme and research results are of great significance to the development of tank bottom in-service inspection robot technology and the realization of equipment localization in China.