The invention provides a collapsible loess tunnel foundation hydraulic high-frequency compaction processing method. The processing method comprises the steps of checking the geological condition of afoundation soil layer and the thickness of a collapsible loess layer within the processing range of a foundation, and determining the vibration-free compaction processing thickness of foundation soil;conducting sampling and carrying out a related indoor soil test; determining the maximum vibration wave velocity; determining the pile hole plane arrangement method, the pile spacing and the hole forming sequence and conducting marking; installing a hydraulic high-frequency controllable device on an excavator, conducting debugging and recording the parameters such as the construction vibration wave velocity, the system pressure and the processing speed; driving the excavator into a tunnel chamber, pressing a hole forming device into the foundation soil layer, pulling out the hole forming device to form a compaction hole when reaching the designed depth; filling and tamping lime soil or cement soil in the compaction hole, or quickly filling a semi-rigid pile forming material and then conducting vibrating tamping and compaction; repeating the procedures to form the composite foundation and completing hydraulic high-frequency compaction processing of the collapsible loess tunnel foundation. Through the processing method, the construction speed can be increased, and the defects in the prior art are effectively overcome.