The invention provides an improved sheathing canal for radial artery puncture. The sheathing canal comprises an outer sheath and an inner sheath which are in sleeve connection. An outer hole is formedin the side wall of the outer sheath. Each of the outer sheath and the inner sheath includes a first end and a second end which are opposite to each other. The inner sheath comprises a canal body, anair bag, an inflation channel, an inner hole and a guide wire channel. The inflation channel is connected to the air bag, and the inflation channel extends along the canal body to the second end. Theinner hole is communicated with the guide wire channel, and the guide wire channel extends to the first end along the canal body. The inflation channel and the guide wire channel are not communicatedto each other. The first end of the inner sheath is additionally provided with the air bag. Due to the fact that the surface of the air bag is more flexible, the vascular damage of a patient is less.The bulging air bag is arranged on the circumference of the wall of the inner sheath, and the end of the inner sheath can be fixed in the center of the air bag to isolate the inner sheath from the vessel wall. In addition, the air bag is elastic, and the diameter can be changed by inflation or water injection, so that the degree of expansion of the vessel wall can be flexibly determined.