Abstract: Frequency response to wind power is not only related to the amount of wind power, but also affected by such factors as wind power access point, AGC control unit, system parameters, and so on. In order to study the key factors that influence frequency quality greatly, a frequency-domain model that considers the dynamic characteristic of generator with governor and AGC, load characteristic and network structure is built to get the explicit expression of transfer function for frequency response in this paper. Based on the model, the influence of wind power access point, AGC control unit, system parameters on frequency dynamic characteristics is analyzed on IEEE 39-bus system by using the amplitude-frequency characteristic curve of transfer function. In the end, combined with measured data of wind power, the influence of AGC on system frequency quality is evaluated by the proposed model.