An embedded lamp and a replaceable illumination module are disclosed. The embedded lamp includes a lamp cover having a hollow housing, and a top frame fixed on the hollow housing. The replaceable illumination module is received in the hollow housing, and includes a connection base for connecting a lamp set, a middle sleeve received in the connection base, a rotation sleeve received in the middle sleeve and protruding outside the middle sleeve, a stop ring fastened at the top side of the middle sleeve, a rotation locking flake fastened at the top side of the rotation sleeve, and a elastic element for pushing the rotation sleeve. When the replaceable illumination module is pushed, the rotation sleeve is rotated in the middle sleeve and fixed at different locations. The rotation locking flake and an opening of the top frame are unlocked when both are parallel or locked when both are vertical.