Saturation-capillary pressure (S-p) relationships of consecutive drainage-imbibition cycles in an air-water two-phase sandy medium were measured for investigation of hysteresis between drainage and imbibition processes. Results show that the degree of hysteresis was obviously not related to the number of the drainage-imbibition cycles, and it decreased with increasing the initial water saturation of the imbibition process in the drainage-imbibition cycle. The S-p relations measured in the tests were fitted with the Van Genuchten (VG) model and parameters of the VG model were analyzed. Results also show that parameter α related to the entry pressure approximated to a constant in all the drainage processes. Both the measured S-p relations and the parameter α indicate that the entry pressure of a medium is a constant, independent from the effects of path and initial water saturation of the drainage process. In the imbibition processes, the parameter α decreased with increasing initial water saturation, which corresponds positively to the change in hysteresis. The VG model is applicable to the description not only of simple S-p relations, but also of S-p relations under complicated drainage-imbibition cycles.