An adapter casing module for installing a power socket includes a first casing and a second casing engaged correspondingly with the first casing, and the first casing has a fixed base, and the second casing has an opening disposed opposite to the fixed base, and the fixed base includes two elastic walls protruded from the first casing, and the two elastic walls are arranged with an interval apart and opposite to each other for installing the power socket between the elastic walls, and a first limit structure is disposed on a side of the two elastic walls, and a second limit structure is disposed on the other side of the two elastic walls, and the first and second limit structures are provided for limiting the power socket to be situated in the fixed base and configured to be corresponsive to the opening of the second casing.