The invention discloses a grid-connection type micro grid reliability analyzing method and a grid-connection type micro grid reliability analyzing system. The analyzing method comprises steps of carrying out equivalent treatment on elements which are arranged in an upper layer power distribution network and can affect micro grid reliability; establishing a micro grid reliability model; establishing a micro grid inner fault effect array; receiving reliability parameters of the elements and inputting the reliability parameters into the micro grid reliability model to simulate a micro grid to run to obtain fault simulation results of the elements; and finding corresponding fault effect types of the fault simulation results of the element in the fault effect array to confirming reliability index of all elements in fault. The analyzing method establishes different-strategy micro grid reliability model to quantitatively analyze effects of different control strategies on micro grid reliability so as to be close to actual running situation of the micro grid and high in assessment result accuracy.