The invention relates to a protective device for a directional penetrating pipeline. The problems that the penetrating pipeline is crushed, damaged and locally deformed are solved. According to the technical scheme, a protective pipeline is arranged outside the penetrating pipeline in a sleeved mode, the length of the protective pipeline is equal to that of the penetrating pipeline needing to be protected, a sealing ring and a slip are arranged at the two ends of a protective pipeline, fluid is filled into a circle between the protective pipeline and the penetrating pipeline, and the pressure of the fluid is smaller than that of internal media in the penetrating pipeline. The slip and the sealing ring seal the annular fluid and tightly hold the penetrating pipeline. The penetrating pipeline is effectively protected, the situation that pipeline is crushed, broken, injured by a crashing object and locally deformed due to wellbore instability is avoided, the penetrating pipeline is prevented from being repaired or replaced or penetrating a new pipeline again, and the protective device is especially suitable for protecting pipelines penetrating through rivers, gravel layers, soft and hard connecting strata, faults and easily-collapsing strata and the like.