Abstract: Along with gradually increase of grid-connected capacity from offshore wind farm (abbreviated OWF), both randomness and uncertainty accompanied with the power generated by OWF affect the planning and operation of power grid even more. At present, the output characteristics of OWF cannot be well researched due to the short of measured date. In allusion to the present situation that the output characteristics of OWF was not adequately researched and based on field-measured operational data of OWF and load characteristics of regional power network, the key problems, which special attention was paid to by power grid operation and scheduling departments, were regarded as the main objects to be researched and the fluctuation law of the main objects to be researched and the fluctuation law of the power generated by OWF was analyzed and summarized from the perspective of qualitative analysis and quantitative analysis respectively. Research results show that the power generated by OWF located at China's South-East coastal areas possesses higher capacity credibility and reveals such a feature that within a whole day the power fluctuation is higher during the daytime and lower during the nighttime and within a whole year the seasonal power fluctuation is higher during the autumn and lower during the summer. Above mentioned results might be utilized in such aspects as scheduling medium- and long-term power generation plan, scheduling decision, capacity allocation for peak load regulation and frequency regulation and so on to provide reference for rational wind power accommodation of large-scale OWF.