Abstract: Jack-ups have been widely used in offshore engineering. The jack-ups will be subjected to environmental loads such as wind and wave currents after installation， so it is necessary to carry out research on their capacity characteristics under horizontal loading. The load bearing characteristics of four-legged jack-up under horizontal loading are analyzed by model tests. The results show that： applying displacement-controlled horizontal load， the horizontal force on the jack-up model basically stops growing after reaching a stable value （450N and 353N for the two clay working conditions， and 75N and 84N for the two sand working conditions， respectively）， while the inclination angle grows linearly with the horizontal displacement. After the horizontal load reaches a certain value， the leg on the windward side of the jack-up platform model will gradually lose its capacity， while the leg on the leeward side will be subjected to increasing vertical， horizontal and bending moment loads. When designing the jack-up platform, it is also necessary to consider the above-mentioned load bearing characteristics of the pile shoe, and carry out a reasonable design and safety assessment of the pile leg and pile shoe.

Key words: jack-up, spudcan, sand, clay, model test