The utility model discloses a side slope-replaceable water drainage pipe. The lower side of a fan-shaped water permeation layer (1) is connected with a fan-shaped water drainage pipe (2) to form a circle; the peripheries of the fan-shaped water permeation layer (1) and the fan-shaped water drainage pipe (2) are wrapped with plastic underdrain filtering layers (3); the peripheries of the plastic underdrain filtering layers (3) are wrapped with cylindrical filtering sieves (4); through holes are formed in parts above the circles of the cylindrical filtering sieves (4); parts below the circles of the cylindrical filtering sieves (4) are closed; the peripheries of the cylindrical filtering sieves (4) are wrapped with at least one geotextile filtering layers (5); the peripheries of the geotextile filtering layers (5) are wrapped with rigid supporting layers (6); the rigid supporting layers (6) are provided with large through holes all around; all the layers are fixedly connected through end openings in a manner of inserting pins (7). The side slope-replaceable water drainage pipe can prevent blocking, is durable and drains water quickly and effectively; secondary seepage is prevented, and an inner structure of the water drainage pipe can be replaced after the water drainage pipe is used for a period of time.