A low noise block down-converter with integrated feed (LNBF) assembly includes an LNBF main body, a connection portion including at least one LNBF locating hole, a support arm including at least one support arm locating hole, at least one locating spring piece including a fix end fixed on the support arm and a locating protrusion, a holder, a holding cam, and a pivot for connecting the holding cam to the holder, wherein when the connection portion inserts into the support arm, each locating protrusion penetrates the corresponding support arm locating hole and the corresponding LNBF locating hole to fix relative position between the connection portion and the support arm, and the holding cam is rotated to make a perimeter of the holding cam abut against the support arm completely and retain each locating protrusions in a penetration state.