Objective：The aim of this study is to evaluate the impact of putrescine on oocyte quality in aged mice during in vitro maturation. Additionally, the effect of putrescine on mitochondria-associated endoplasmic reticulum membrane (MAM) in aged mouse oocytes will be investigated. Methods: GV stage mouse oocytes were cultured in vitro until they reached the MII stage. The young control group consisted of 8-week-old mice, while the old control group consisted of 40-week-old mice. The old experimental group consisted of 40-week-old mouse oocytes supplemented with 0.5 mM putrescine in the IVM solution. The assessment of oocyte quality involved the detection of the PB1 extrusion rate, 2-cell rate, blastocyst formation rate, cortical granule distribution, spindle abnormality rate, and chromosome abnormality rate of oocytes at stage MII. Additionally, MAM was observed using transmission electron microscopy, and the Ca2+ levels in mitochondria, endoplasmic reticulum, and cytoplasm were determined using Ca2+ probes. Mitochondrial function was assessed by measuring mitochondrial membrane potential, ATP content, and ROS levels. Results: Putrescine increased the rate of PB1 extrusion and the blastocyst rate in aged oocytes and significantly reduced the rate of cortical granule distribution abnormalities, spindle abnormalities and chromosomal abnormalities. The oocytes contained MAM structures, and putrescine prevented the shortening of MAM spacing in aged oocytes. Meanwhile, putrescine improved mitochondrial function and reduced intracellular ROS levels by alleviating mitochondrial calcium overload caused by rapid Ca2+ transfer between MAMs. Conclusion: The addition of putrescine to in vitro maturation cultures significantly improved the quality of aged oocytes. Putrescine also alleviated mitochondrial calcium overload and improved mitochondrial function by modulating inter-MAM Ca2+ transfer.