The invention discloses an island microgrid black start system and method. According to the system, a direct-driven wave power generation system is taken as a black start power source, the black start power source is connected with an island microgrid main network through a transmission line, the direct-driven wave power generation system comprises multiple branches, each branch comprises a wave power generation set, a PWM rectifier and a PWM inverter, and a grid connected point of the island microgrid main network and the direct-driven wave power generation system is provided with energy storage equipment and a reactive power compensation device in a parallel mode. The method comprises steps that the direct-driven wave power generation system is taken as the black start power source, and a direct-driven wind power generation set is taken as the black start power source; the wave power generation sets, the energy storage equipment and the reactive power compensation device are employed to realize coordination control, and the wave power generation sets can be sequentially switched in to recover island microgrid power supply. The system is advantaged in that the auxiliary equipment is simple, and properties of fast start speed and low operation cost are realized.