Canine cloning have been succeeded for a decade. To obtain in vivo matured dog oocytes, Serum progesterone (P4) level were employed for ovulate determination. However, accuracy of P4 methods is not satisfied. The aim of this study was to compare both methods of serum estradiol (E2) and P4 on the accuracy of canine ovulation determination. Canine serum P4 and E2 concentration during both proestrus and estrus were detected. Correlation between accuracy of each method and environment temperature were analyzed. Following ovulation, oocytes were collected by surgery. As a result, higher percentage of mature oocytes was obtained when using E2 (56.43%) as compared to P4 (39.60%). Accuracy of P4 increased from spring (30.76%) to summer (47.92%) and decreased in autumn (37.50%) and winter (29.16%) gradually. Especially, E2 maintained about 50% to 65% whatever the season and temperature. Correlation analyze showed that dynamic of P4 accuracy highly correlated with environment temperate (Rp4=0.862) but E2 could not be affected by the temperature (RE2=0.199). To determine whether obtained oocytes by E2 method could be used for canine cloning, twenty canines were selected as oocyte donors, and two puppies were produced after somatic cell nuclear transfer(SCNT) and embryo transfer(ET) with the oocytes by E2 method. In conclusion, comparing to the P4 method, the E2 is an accuracy and reliable method for canine cloning.