Abstract: In response to the high risk of falling during high-altitude maintenance operations such as substation roof climbing, as well as the problems of long braking distance and low protective effect of traditional fall prevention devices, we have designed a roof safety climbing ladder mobile fall prevention device. Firstly, we started with material selection, using high-strength aluminum alloy, wear-resistant bearing steel, and corrosion-resistant stainless steel to ensure the reliability of the device in complex outdoor environments; We have designed a four-wheel guided sliding track type following mechanism, which can achieve low resistance and smooth following, laying the foundation for continuous protection; By integrating IMU sensors and adaptive threshold algorithms, we have achieved rapid recognition of the initial stage of a fall; We have adopted a dual locking mechanism with electronic triggering as the main method and mechanical centrifugal triggering as the auxiliary method, combined with a wedge-shaped self increasing force locking mechanism, to ensure fast and reliable braking after falling. By building a simulation experimental platform and using a 100kg dummy as the load, tests were conducted at two fall heights of 0.5m and 1.5m. The results showed that the maximum braking distance of the device was less than 50mm, and the maximum impact force was less than 4.5kN. All performance indicators were superior to traditional fall protection devices, and it performed stably in repeated experiments, achieving fast response and smooth braking safety protection during high-altitude climbing. It can provide effective technical support for high-altitude operation scenarios such as substations.