Objective To investigate the morphology and distribution of cortical granules, mitochondria, microfilaments, spindles, and chromosomes in aged mice. Methods Kunming mice were divided into a young (4-8 weeks) and a old age group (48-52 weeks). Female mice were injected intraperitoneally with 10 IU prenant mare serum gonadotropin (PMSG), and followed 48 hours later by 10 IU of human chorionic gonadotrophin (hCG). MII oocytes were collected from the oviducts 14 hours after the hCG injection into M199 medium. The cumulus cells were removed by a brief incubation. Oocyte-corona-cumulus complex(OCCC) in fallopian tube were collected by superovulation to female mice. Anti-mouse α-tubulin monoclonal antibody was used to label the spindle microtubules, phalloidin labeled actin rhodamine to label microfilaments, lentil lectin combined with FITC to label cortical granules and Mito Tracker Green FM to label mitochondria. The specimen was examined under a laser scanning confocal microscope. Results Totally 372 oocytes were obtained, 179 oocytes from the young group and 193 oocytes from aged group. The abnormal rate of spindle of elderly mouse oocytes (71.78% ± 1.27%) was significantly higher than that of young mice (18.93% ± 1.27%) (P<0.01). The elderly mouse oocytes chromosomes arranged abnormal rate (65.16% ± 1.52%) was significantly higher than that of young mice (32.24% ± 1.10%) (P<0.01). Fluorescence intensity of aged mouse oocyte mitochondria (28.09 ± 6.62) was significantly lower than that of young mice (45.07 ± 5.90) (P<0.01). The aged mouse mature cortical granules (grade III cortical granules) rate (51% ± 1%) was significantly lower than that of young mice (94.04% ± 0.71%) (P<0.01). Conclusion The abnormal rate of aged mouse oocytes’ major organelles and cytoskeleton increased significantly than that of the younger mice, which may be the main reason for the low pregnancy rate in the elderly.