Abstract: In order to increasing the reproductive capacity of Tibet-mastiff, perfecting artificial insemination（AI）technology and preserving spermatozoa of excellent Tibet-mastiff. We had collect and frozen the semen of eight Tibet-mastiffs, at the same time, had a systemic filtrate to the spermatozoa freezing-extender of Tibet-mastiff. The result showed that the extenderⅤ(composing by glucose 1.98 g, sucrose 3.42 g, citric acid sodium 0.59 g, glutamic acid sodium 0.75 g, EDTA-Na2 1.21 g, vitamin B6 10 mL, vitamin B12 10 mL,yelk 20 mL and glycerol 8 mL) is the best cryopreservation extender of Tibet-mastiff. The forward motility sperm is 0.58, pathomorphology sperm is 17.2%, meeting the quality criteria apply for AI and storage at -196 ℃.

Key words: Tibet-mastiff; collect semen; semen; sperm; spern motility; abnormality ratio