[Objectives]  To solve the problem of insufficient pollinating insects for alfalfa and improve seed production. [Methods]  The pollination of alfalfa by Apis mellifera and Bombus terrestris was compared. [Results]  There was no significant difference in daily working time and preferred foraging temperature of each species, but their foraging behavior differed significantly. Bombus terrestris were more likely to open the carina due to their greater body weight and made significantly more visits to flowers than Apis mellifera. However, they spent less time visiting individual flowers than Apis mellifera. There was no significant difference in fruiting rate and yield per plant after pollination by each species. Bee species, the rate of carrying pollen to nests and flower visiting frequency, are the main factors that affect alfalfa seed production. [Conclusion]  Apis mellifera and Bombus terrestris are both effective pollinators of alfalfa, but Apis mellifera is more suitable for large-scale alfalfa seed production because of the more established management technology available for this species and their relatively low cost.