Pushover tests of an aluminum model pile in saturated loose sand were conducted at the National Center for Research on Earthquake Engineering(NCREE) of Taiwan. The test data were analyzed to investigate the lateral loading-unloading response of the pile. The pushover curves of the pile show a significant loop of hysteresis. The p-y curves obtained also exhibit remarkable hysteretic response. The backbone curves of the p-y curves can be expressed by the secant subgrade reaction modulus which is a function of depth and lateral displacement. The hysteresis locus of the p-y curves can be simulated by the backbone curves with the unloading-reloading model of Masing type to give consistent pushover curves to the measured.