Fresh subcutaneous tissue from the rabbit's ear was processed with copper ferrocyanide method (Karnovsky and Roots, 1964) for demonstrating acetylcholinesterase. The arterio-venous anastomoses were revealed by the abundant "cholinergic" nerve fibers present around its arterial and intermediate segments. These nerves formed a dense network around these segments of AVA which gives AVA a conspicuous and outstanding picture under the microscope. 262 AVA were identified and their length and outer diameter of the intermediate segment were measured. The longest was 620.6 ?m, the shortest 81.9 ?m, and the averaging length was 254.8 ?m. Their outer diameters fell between 109.2～20?m, with an average of 52.2 ?m. The authors condered the measurements of the intermediate segment of the AVA give more significant information than the total length of the AVA.The AVA were classified into the following types according their morphological characteristics: the simple type (including the long and thin type, and short and thick type) and the complex type (including bifurcate, trifurcate, quarifurcate, compound, and circular types). This method of demonstrating AVA morphology was compared with former observations made directly in vivo or by histological methods and it serves as an new tool for the investigation of AVA.