The present invention discloses an interlock attaching strap system, comprising a carrier having a plurality of first webbing strips transversely, evenly and spacedly affixed thereon, a holder having a plurality of second webbing strips transversely, evenly and spacedly affixed thereon, wherein by overlapping the carrier and holder, the first webbing strips and the second webbing strips are capable forming an elongate interlocking channel; at least an elongated interfering strap, which is longitudinally extended on the holder, having an affixing end extended from a peripheral edge of the holder and a free tab end, arranged to slidably pass through the interlocking channel and is hooked onto the last webbing strip so as to securely reinforce the holder on the carrier via the interfering strap.