The invention provides a prefabricated distribution box wiring tube pre-embedded building block. The prefabricated distribution box wiring tube pre-embedded building block is composed of a groove cavity block and a door inserting block, and the width of the groove cavity block is larger than the total span width of all wiring tubes of a distribution box; the door inserting block is an inserting plate with a T-shaped section, and a T-shaped inserting hole is formed in the groove cavity block; an inner groove is further formed in the rear side of the T-shaped inserting hole and is a wiring tubecavity; the groove cavity block and the door inserting block are each of an integrally poured concrete structure; the heights of the groove cavity block and the door inserting block are designed to bethe height from the bottom of the designed distribution box to the ground; and the length from the left side of the groove cavity block to the left side of a wall is an integral multiple of the length of a bricklaying brick, and the length from the right side of the groove cavity block to the right side of the wall is an integral multiple of the length of the bricklaying brick. According to the prefabricated distribution box wiring tube pre-embedded building block, the distribution box wiring tube is packed through the wiring tube building block formed by internally pouring, the quantity valve that the position of the wiring tube is not matched with the specification of the bricklaying brick of the wall is eliminated, the building block is just like 'eating the excess length', when the wall is laid, brick cutting is not required, the whole piece of bricklaying brick is laid, the wall laying work is facilitated greatly, and the working efficiency is improved.