Abstract: An automatic horizontal catwalk is developed to improve the working conditions of pipe transportation for drilling and working operations of offshore modular drilling rigs, reduce the labor intensity and improve the working efficiency. The catwalk adopts fixed large capacity pipe rack, horizontal mobile cart and trolley, single arm supporting manipulator and other structures, and adopts electric control fluid and load sensing system to realize automatic transportation of drilling pipe. The PLC control, industrial ring network and integrated control technology are used to remotely control the equipment; and safety logic interlocking control and emergency operation functions are set to improve the safety and reliability of the system. The finite element analysis software is used to check, calculate and optimize the equipment to meet the strength and stiffness requirements. The site test results show that the equipment has normal operation functions, can successfully complete the horizontal transportation of pipe tools, and can cooperate with the wellhead lifting equipment to achieve the horizontal and vertical conversion of pipe tools. The technology is advanced, and the degree of automation and efficiency are high. The site operation can significantly reduce the labor intensity of workers, and realize the less and unmanned operation of the drill floor.