The probiotic function and structural properties of recrystallised sweet potato starch before and after in vitro digestion were studied. The results demonstrated that the annealed, temperature-cycled and heat-moisture treated sweet potato starches before and after in vitro digestion could resist the degradation of tract enzymes and selectively promoted the proliferation of Lactobacillus, Bifidobacterium, Fecal streptococci and Clostridium septicum in human feces. Compared with the annealed, temperature-cycled and heat-moisture treated sweet potato starches, the digested annealed, temperature-cycled and heat-moisture treated sweet potato starches possessed the more stable structure as well as the higher selective proliferation of probiotics. Therefore, the recrystallised sweet potato starches could accord with the conditions of prebiotic, and be further studied as the new prebiotic product.