The invention discloses a weep hole structure and method capable of avoiding blocking. The weep hole structure comprises a through hole in a retaining wall and a filter device installed inside the through hole. A main pipe of the filter device is filled with macadam filtering layers and a sand filtering layer, and a first filter cap and a second filter cap are packaged at the two ends of the main pipe; the middle of the first filter cap is concave, and the lowest point of the concave part is located on the axis of the main pipe; the outer surface of the main pipe is provided with key teeth; the main pipe is sleeved with an inner pipe; the second section of the inner pipe is provided with key grooves in fit with the key teeth; the inner wall of the third section of the inner pipe and the outer surface of the second filter cap are sealed and bonded through a bonding layer; at least the outer surface of the fourth section of the inner pipe is in a prism shape; a pressing ring is fixed to the left end of the inner pipe; the right end face of the pressing ring is tightly pressed on the first filter cap; an outer pipe is fixedly installed in the through hole of the retaining wall; the outer pipe and the inner pipe are connected and installed together in a sleeved mode through threads; the left end of the outer pipe is provided with an outer turnup; a sealing ring is arranged between the outer turnup and the retaining wall. The weep hole structure can prevent water and soil loss and is not prone to being blocked.