Cantilever plate is a common kind of structure in aerospace field. Due to its large deflection, low-frequency vibration problem is relatively serious. Active vibration of a kind of cantilever Kagome sandwich plate is studied here. First, the finite element models of the cantilever structure and piezoelectric actuator are established. Then the active control strategy of cantilever Kagome sandwich plate is proposed by combining independent modal space control with modal observer. And, aiming at one kind of gust load, the independent modal space control of Kagome sandwich plate is simulated, while focus is on the influence of observer poles on the control effect. The results show that this control method can significantly improve the damping properties, while greater attenuation factor of the observer can get better control effect. Therefore, Kagome sandwich panels has obvious advantages over traditional board structure in vibration control aspect.