Compared with conventional surfactants, sodium cholate has a special self-assembly behavior, which is due to its unique rigid steroid skeleton and amphiphilic structure. The self-assembly behavior of sodium cholate was characterized by small-angle X-ray scattering, isothermal titration calorimetry and zeta potential measurement. Aggregation driving forces of self-assembly behavior change are discussed, It was found that in the concentration range of 20mg/mL, hydrophobic interaction and hydrogen-bond interaction reached a balance. With the increase of concentration, the driving forces of hydrogen bond gradually became dominant. Through the model fitting analysis of small angle X ray scattering results, the specific shape and size information of sodium cholate was obtained, The long axis radius of sodium cholate self-assembly is between 13.5-41.2 , and the short axis radius is between 9.6-11.4 . When the concentration reaches 40 mg/mL, the self-assembly of sodium cholate reaches the maximum size.