The protein characteristics of 9 kinds of commercial Asini Corri Collas (ACC, E1—E9) were compared, including amino acid composition, pI, secondary structure and molecular weight distribution. The differences of pI were negligible and all samples showed a range of 4.38—4.88. Circular dichroism results indicated that only random coil configurations was observed of all ACC samples due to the damage of triple helix structures. The amino acid composition was similar other than some differences in imino acid (Pro and Hyp) composition. E2, E3, E4 and E9 showed lower imino acid content (<23.80%) than that of others (>25.0%). Significant differences in the molecular weight distribution were observed. E2, E4, E7 and E8 appeared to be in a wider distribution containing more high molecular weight (>4.46%) and the major MW fraction was located in the range of 120-132 kD. The other 5 samples, however, showed a narrower distribution (high molecular weight protein <1.16%) and the major MW fraction was located in the range of 36-42 kD. The difference in protein characteristics of commercial ACC attributed to the differences in degradation degree of protein. This study would improve the protein characteristics evaluation system of ACC and lay a foundation to further study the effect of processing on protein characteristics.