BACKGROUND: In recent years, the demand for in vitro maturation of immature oocytes has increased. Oocyte maturation is affected by many factors, among which the selection of medium is particularly important, and there is currently no unified plan. OBJECTIVE: To compare the in vitro maturation of germinal vesicle stage oocytes with different maturation media and to investigate its effects on oocyte quality and developmental potential. METHODS: Germinal vesicle oocytes were matured in G-1TM PLUS medium, CZB medium and M16 medium, and mature oocytes in vivo were used as control group to compare in vitro fertilization and early embryo development among various groups. The immunofluorescence method was used to evaluate mitochondrial function in mature oocytes of each group. Calcium oscillation was detected by confocal microscopy real-time imaging system. RESULTS AND CONCLUSION: (1) There was no significant difference in the first polar body ejection rate among the three groups (P > 0.05). (2) The rate of in vitro fertilization was higher in the G-1TM PLUS group (52.86±11.24)% than that in the M16 group (37.76±6.70)% and the CZB group (30.62±5.51)%. The blastocyst rate was lower in the CZB group (36.23±6.63)% than that in the control group (78.16±4.17)%, G-1TM PLUS group (55.75±7.63)% and M16 group (53.36±6.33)%. (3) Compared with the control group, the length-to-width ratio of the spindle in the CZB group increased (P < 0.005). (4) The mitochondrial function of the CZB group was worse than that of the control group, G-1TM PLUS group and M16 group, and abnormal mitochondrial agglutination occurred in the CZB group. (5) The frequency of calcium oscillations in the CZB and M16 groups was significantly higher than that in the G1 and control groups. In conclusion, during in vitro maturation of mouse oocytes, in vitro maturation rate was not significantly different among G-1TM PLUS, CZB and M16 media, but the G-1TM PLUS medium had a higher rate of fertilization and blastocyst formation. [ABSTRACT FROM AUTHOR]