The conventional component based approach to load modeling has the disadvantages of huge data collection work and too low accuracy to meet the needs for time-varying characteristics. By simplifying data acquisition with spot check and statistics， the power data at the user side and substation side obtained separately from the load control center and EMS can be used to efficiently realize component based on-line modeling for electric loads. The user's electric consumption information and other related information is usually updated in the load control center， so dynamic and long-term management of the synthetic load parameters can be realized. The method has been utilized in Fujian Power Grid with satisfactory results.