Objective To develop an reliable method to measure Young's modulus of zona pellucida of animal oocytes in a quasi-static statue. Method Elastic sphere model embracing incompresive liquid was adopted to study in vitro mechanical properties of zona pellucida of baffalo oocytes by using micropipette aspiration technique. Based on mechanical analysis, a formula was derived to calculate the Young's modulus of Zona Pellucida in a quasi-static statue. Results A total of 20 mature non-polus oocytes were evaluated within a rather large strain span at temperature of 24～26℃. Their mean Young's modulus E was 2.2×104 Pa, suggesting a good linear elastic property. Conclusion This study provided an effective method to measure elastic property of zona pellucida of animal oocytes.