A base for pet feeder and a pet feeder for eating or drinking of pets are provided. The base includes a main body portion and a plurality of adjusting mechanisms. The main body portion includes a first side and a second side, the second side is disposed opposite to the first side, and the first side is configured to contain food or water. The plurality of the adjusting mechanisms are disposed at the second side of the main body portion at intervals, each of the plurality of the adjusting mechanisms is capable of providing at least three heights. Each of the plurality of the adjusting mechanisms includes a first supporting plate and a second supporting plate. The first supporting plate includes a first part and a second part, the first part is rotatably connected to the second side.