Luteinizing hormone (LH) is one of the main pituitary hormones that regulate ovulation, however its role has not been studied in giant panda. In this study, we developed an ELISA method for the detection of panda urinary LH. We analyzed urinary hormones of 24 female pandas during 36 breeding periods, we found females could easily be impregnated if the first mating occurred within 10 hours after LH peak. We also found the patterns of the ratios of urinary LH and progestagen in pandas that bred and successfully gave birth were significantly different from those that bred but failed to give birth. These data was the first to provide the urinary LH profiles during the estrous and gestational periods in pandas, and demonstrated that the appearance of the urinary LH peak indicated the timing of ovulation. The LH detection together with estrogen analysis makes the window for successful mating narrower than previously reported. Moreover, detection of urinary LH and progestagen can be used to discriminate between pregnancies and pseudopregnancies/miscarriages in the species. Thus, our findings suggest that LH not only plays a critical role in regulating ovulation but also plays an important role in maintaining pregnancy in the giant panda.