The formation of bundles of ultralong nanobelts by an anion biological surfactant sodium cholate (SC) and a cationic dye (MB) through ionic self-assembly approach was obtained. The nanobelts possess smooth surfaces, flat end facets and solid internal structure. This one dimensional self-assembly is dominated by the π–π stacking interactions between MB molecules in concert with the hydrogen bonding between SC molecules. The shape and length of the bundles of SC/MB nanobelts could be easily controlled by changing the SC concentration and the aging temperature. Moreover, the electrocatalytic properties of the SC/MB nanobelts modified electrode were also investigated and the results indicated that the bundles of ultralong SC/MB nanobelts exhibited efficient electrocatalytic activity towards l-ascorbic acid (AA) in phosphate buffer solution (pH = 7.0). In addition, the electrostatic interaction between AA and MB also facilitates the electrons transfer on the surface of the GCE and promotes the oxidation of AA. The present work provides an alternative way to design and fabricate the ultralong 1D nanobelt structures with tunable sizes using small organic molecules. This system may also open up a way for the design and development of optical and electronic devices in the potential bio-applications and electrocatalyst for fuel cells.