UHVDC power transmission is a better solution for large-scale transmission of wind farm. Based on DIgSILENT, the wind-coal-bundle islanded system with UHVDC link model is built, and studied on the wind power fluctuations on the flow effect of AC bus voltage and frequency. The control strategy of DC system not fully follows power fluctuations by DC power modulation was proposed, and studied the influence of key parameters on DC delivery system. The simulation results show that The simulation results show that, the DC power modulation provides an effective means for the inhibitory effect of wind power fluctuation of wind-coal-bundle islanded system with UHVDC link. The key parameters of modulation gain value is greater, the voltage stability improvement worse, frequency stability improvement better.