The extracorporeal culture and mature method of immature oocyte from ovary tissue block includes selecting marrow mesenchyme stem cell MSC of female mouse as the feeder cell, compounding MSC culture liquid and agar and covering the culture rack, adding HCG in 3 IU/ml, and adhering the ovary tissue block on the rack to culture. In the co-culture system, estradiol, progestin and luteotopin contentsare increased obviously, and after culturing, there is mature oocyte discharged. The method is significant in surviving rear endangered species of animals, breeding fine variety of animal, cell biological research of embryo stem cell, etc.