Yak skin was utilized to prepare the acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC), whose structure and property had been analyzed. The results showed that the extraction rates of ASC and PSC were (54±0.18)% and (78±0.42)%, respectively. The results of ultraviolet absorption spectrum analysis, infrared absorption spectrum analysis and electrophoresis analysis showed that both ASC and PSC had a complete three strand helical structure, which conformed to the structural characteristics of I type collagen. Amino acid analysis indicated that ASC and PSC were rich in imidates at 264.1 residues/1000 residues and 276.6 residues/1000 residues. The thermal stability of ASC and PSC was 41.5 ℃, 47.5 ℃, and the heat shrinkage temperature was 62.5 ℃, 70 ℃. The thermal stability of PSC was higher than that of ASC. ASC and PSC were observed by scanning electron microscopy (SEM) to determin the loose and irregular morphology. Self-assembly experiment illustrated that both ASC and PSC performed the fiber forming ability. Self-assembly experiments showed that PSC and ASC have certain fiber-forming ability, and the D-periodicity of self-assembled products was (68.2±5) nm nm and (69.3±3) nm, respectively, and PSC was assembly faster than ASC.