Abstract: Thirty -six ejaculates from six male dogs were diluted, quilibrated and packed in 0.5ml straws simultaneously, the only difference being in the programs used for freezing. The straws were rozen with programⅠand programⅡin the programmable freezer separately. The mean post thaw progressive motility （PTPM）were 0.47±0.10 and 0.34±0.05 (P＜0.01) resp., and the percentage of sperms with intact acrosome were 34.47±5.20 and 29.77±4.37（P＜0.01)resp. It is concluded that the programⅠwas better than program Ⅱfor freezing canine straw semen.