This experiment was designed to determine the influence of boron priming on seed vigour in thirteen varieties of alfalfa (Medicago sativa L.). Alfalfa seeds were primed with 1.8% (W/V) concentration of borax solution for 0, 3, 6, 9, 12 and 24 h at 20°C. The results showed that the original vigour of alfalfa seeds was disparate in thirteen varieties and there were highly significant (P less than 0.01) differences observed in both varieties and priming time and their interactions on the vigour of the seeds. Alfalfa seeds of WL525HQ and WL656HQ might be more sensitive to boron toxicity, but seeds of WL298HQ, WL343HQ, WL354HQ, WL903 and Pianguan were insensitive to boron toxicity. Thus, it is necessary to carefully select appropriate varieties of alfalfa seeds for the application of boron priming.