Abstract: Frequency is the key indicator for island microgrid, but it can be affected by the renewable energy fluctuation and the load variation. The robust coordinated control strategy is proposed for the photovoltaic (PV) -diesel-battery isolated microgrid. Based on different frequency deviation ranges, PV systems and diesel generator (DG) systems are prioritized for frequency regulation. When the frequency deviation exceeds the set frequency threshold, the battery system begins to response quickly. Furthermore, the sliding mode (SM) load frequency control (LFC) is designed to improve the dynamic characteristics of the coordinated strategy and restrain the randomness and volatility of the source and load. The results of Matlab/Simulink prove that the proposed coordinated strategy can make full use of renewable energy and improve the frequency quality.