Cobalt-Nickel (CoNi) alloy nanotubes (NTs) with diameters 50 nm (D1), 100 nm (D2), 150 nm (D3), and 200 nm (D4) have been fabricated using Anodic Aluminum Oxide (AAO) membranes. X-ray diffraction spectroscopy (XRD), field-emission scanning electron microscopy (FE-SEM), vibrating-sample magnetometer (VSM), and physical property measurement system (PPMS) analysis methods were employed to systematically investigate the structural, morphological and magnetic properties of CoNi NTs samples. Magnetization reversal mechanism has been explained by angular dependence of coercivity. Low temperature studies have shown that coercivity Hc of nanotubes follows the thermal activation model. Temperature dependence of Hc follows the 3/2 power law for the field dependence of energy barriers.