A method of signaling of coding mode including an Intra-block copy mode, IntraBC mode, and inter prediction mode for a picture, wherein the picture is divided into multiple coding units, the method comprising: receiving input data associated with a current prediction unit in a current picture; if the IntraBC mode is selected for the current prediction unit: encoding or decoding the current prediction unit using an IntraBC predictor derived based on an IntraBC reference picture selected from a reference picture list, wherein the reference picture list corresponds to reference picture list l0 or reference picture list l1 used for Inter prediction, and wherein the reference picture list includes the IntraBC reference picture containing one or more previously reconstructed IntraBC blocks and zero, one or more Inter reference pictures corresponding to zero, one or more previously reconstructed Inter-coded pictures; generating a first reconstructed current block after said encoding or decoding the current prediction unit; and updating the IntraBC reference picture according to the first reconstructed current block, characterized in that the IntraBC reference picture is inserted in the reference picture list after an existing Inter reference picture in the last position or in another specific position, respectively, referred to as selected position, and in that the selected position is signaled in a sequence level, picture level, or slice level, or in that the selected position is inferred. receiving input data associated with a current prediction unit in a current picture; if the IntraBC mode is selected for the current prediction unit: encoding or decoding the current prediction unit using an IntraBC predictor derived based on an IntraBC reference picture selected from a reference picture list, wherein the reference picture list corresponds to reference picture list l0 or reference picture list l1 used for Inter prediction, and wherein the reference picture list includes the IntraBC reference picture containing one or more previously reconstructed IntraBC blocks and zero, one or more Inter reference pictures corresponding to zero, one or more previously reconstructed Inter-coded pictures; generating a first reconstructed current block after said encoding or decoding the current prediction unit; and updating the IntraBC reference picture according to the first reconstructed current block, characterized in that the IntraBC reference picture is inserted in the reference picture list after an existing Inter reference picture in the last position or in another specific position, respectively, referred to as selected position, and in that the selected position is signaled in a sequence level, picture level, or slice level, or in that the selected position is inferred. encoding or decoding the current prediction unit using an IntraBC predictor derived based on an IntraBC reference picture selected from a reference picture list, wherein the reference picture list corresponds to reference picture list l0 or reference picture list l1 used for Inter prediction, and wherein the reference picture list includes the IntraBC reference picture containing one or more previously reconstructed IntraBC blocks and zero, one or more Inter reference pictures corresponding to zero, one or more previously reconstructed Inter-coded pictures; generating a first reconstructed current block after said encoding or decoding the current prediction unit; and updating the IntraBC reference picture according to the first reconstructed current block, characterized in that the IntraBC reference picture is inserted in the reference picture list after an existing Inter reference picture in the last position or in another specific position, respectively, referred to as selected position, and in that the selected position is signaled in a sequence level, picture level, or slice level, or in that the selected position is inferred.