A modularized server includes a main housing, a first block unit, a second block unit, and a removable module. The main housing has a first inserting groove and a second inserting groove, and the removable module has a guide channel. When the removable module is disposed in the first inserting groove along a sliding direction, the first block unit is located in the guide channel. Moreover, the second block unit blocks the removable module from being installed to the second inserting groove.