The invention relates to a life cycle cost considered microgrid system economic evaluation method. The method is technically characterized by including steps: step 1, constructing a device-level costmodel of a whole microgrid system; step 2, constructing an energy-level cost model of the whole microgrid system; step 3, constructing a life cycle economic benefit mathematical model of the whole microgrid system; step 4, constructing a life cycle cost considered microgrid system economic benefit evaluation model; step 5, adopting a global particle swarm optimization algorithm for economic benefit evaluation of the life cycle cost considered microgrid system, and calculating a maximum microgrid economic benefit value. By calculation of microgrid benefits according to microgrid and power gridpower exchange characteristics, high effectiveness and accuracy are achieved, and references are provided for microgrid economic benefit evaluation.