Ag-In-Cd alloy is widely used as the control rod material in the pressure water reactor (PWR),so it is very important to research the compressive creep behavior for understanding the mechanical property of control rod materials in pile. The compressive creep behavior of as-cast Ag-In-Cd alloy was investigated using a special apparatus at 300—400℃ and under compressive stresses in the range of 12—24 MPa in this work. The stress exponent n and apparent activation energy Q_a of the creep process have been calculated as well as the mechanisms of compressive creep behavior have been discussed. The results show that the compressive creep of the alloy increases with the increase of temperature and compressive stress. The relationship between steady creep rate and stress can be expressed in a power law form. The stress exponent n are 2.90, 4.09 and 5.77 at 300, 350 and 400℃ respectively. The apparent activation energy Q_a of the creep process are 68.1, 103.7 and 131.6 kJ/mol under compressive stresses of 12, 18 and 24 MPa respectively. Stacking fault is the primary rate controlling mechanism for the Ag-In-Cd alloy at 300—400℃ and the compressive stress range of 12—24 MPa, which was deduced from TEM observation.