Microgrid contains multiple distributed resources, and the problem of capacity configuration for hybrid power occurs when microgrid is built. Taking the building of a certain island microgrid for example, the method of capacity configuration for hybrid power in microgrid is researched. Through case analysis, it is certain that the configuration meeting comprehensive load demand is suitable for capacity configuration on the basis of intentional islanding, while the configuration meeting significant load demand is suitable for capacity configuration on the basis of unintentional islanding. The former puts particular emphasis on the time of unintentional islanding for the lowest investment cost in the situation of meeting comprehensive load demand, and the latter puts particular emphasis on guaranteeing significant load sustainable supply whenever islanding occurs. In addition, capacity configuration can be carried out by combining both of them. As a result, not only comprehensive load demand can be met under intentional islanding, but also significant load demand can be met under unintentional islanding.