Provided is an installing method of an elevator without a machine room in a multi-story building. According to the installing method of the elevator without the machine room in the multi-story building, a lift-way is of a multilayer steel framework structure, integral hoisting is conducted after welding forming, and meanwhile a pre-embedded steel plate is arranged on a wall of one side of a staircase in an existing building, the pre-embedded steel plate and a civil structure of the existing building are integrally connected, the pre-embedded steel plate and a steel framework are connected and installed inside the lift-way, the lift-way is arranged outside a window of an existing staircase, a guide rail is arranged in the lift-way, a dragging mechanism is arranged at the top of the lift-way, an elevator car is arranged in the lift-way, a window in each staircase of the corresponding story is transformed into an elevator landing door, and an elevator control cabinet of the elevator is arranged at an elevator landing door of the top story. The installing method of the elevator without the machine room in the multi-story building has the advantages that the purpose of installing an elevator on the multi-story building, especially on a brick and concrete multi-story building without destroying a main structure of the existing building is achieved, time of construction is short, the going out of residents is not influenced during the construction period, the occupied space is small, safety is high, and construction efficiency is high.