Prebiotics play an important role in promoting the growth of probiotics and regulating the intestinal microflora balance. To explore the prebiotic characteristics of crude Lanzhou Lily (Lilium davidii var. unicolor) oligosaccharides (CLOs), the CLOs were extracted and characterized from dried Lanzhou lily, and the hydrolysis of CLOs in artificial gastrointestinal solution as well as the effects on acid production and proliferation of Streptococcus thermophilus ATCC-14485 and Lactobacillu bulgaricus ATCC-11842 were determined by using FOS and inulin as positive controls. The results showed: the molecular weight of CLOs was 1 194 Da, and mainly consisted of mannose, arabinose and glucose with a molar ratio of 1 : 3.57 : 16.40; the hydrolysis ratio of CLOs in artificial gastrointestinal solution was 26.96%, which was significantly lower than that of inulin (P < 0.05); the promotion effects of CLOs on acid production by lactic acid bacteria was significantly better than that of inulin and FOS (P < 0.05); the addition of CLOs at 1.0%（W/V）could effectively promote the proliferation of S.thermophilus and L.bulgaricus, and slow down the death rate of both during the shelf life. These findings suggested that CLOs possess prebiotic characteristics, and can provide a theoretical basis for developing a novel symbiotic fermented milk.