Surfactant self-assembly has been extensively studied in aqueous solution at room temperature or above, but it was less documented at temperatures below 0 °C. Our preliminary work showed the nonionic surfactant 2,2'-(Octadecylimino)diethanol can dissolve in alcohol/water co-solvent and displays excellent thickening power, and the rheological property is remarkably changed upon decreasing temperature blew 0 °C. Here, we request Rheo-SANS beamtime on SANS2D to simultaneously characterise the surfactant micellar structure and bulk solution properties from room temperature to subzero temperature. The results will enable us to correlate the rheological data with the size and shape of the self-assembled structures. The findings will expand the knowledge of surfactant self-assembly at low temperature and promote practical applications of surfactant solution in extremely cold environment.