The invention relates to an online monitoring and early warning system for vibration of an intelligent motor, which belongs to the field of intelligent motor monitoring. The system comprises a vibration sensor, a processing and analysis module, a calendar module, a storage module, a communication module, a field alarming module and a portable device. the vibration sensor measures the real-time vibration data of the motor, the data are transmitted to the processing and analysis module, the operation and the working state of the motor are analyzed and judged in combination of data measured by an electric parameter measuring module and a rotation speed measuring module, and in view of abnormal vibration features under different load rates, field alarming or early warning to the portable device is carried out. Besides, early warning is also carried out for the changing trend of the vibration frequency and the changing trend of the amplitude. The system can realize online vibration monitoring and early warning when the motor is abnormal or in an abnormal working state, timely finding and timely processing are carried out, expanding of motor fault can be effectively avoided, the maintenance efficiency is greatly improved, the structure is simple, the cost is low, the measurement is accurate, and the system can be widely applied to intelligent and online vibration monitoring on middle and small-sized motors.