Chromium white-cast iron containing crystallized graphite (abbreviated as the A-alloy) may be considered as a composite-casting-material due to its structure consisting of three phases with different properties; M₇C₃ type eutectic carbide, austenite matrix, and graphite. Chromium white-cast iron containing crystallized graphite possesses both good wear resistance and strength similar to high chromium white-cast iron. Furthermore, it also possesses good lubricity due to the graphite; therefore, it is used as a material for finish rolls of stainless steel. The purpose of this study is to clarify the high-temperature compression-strength mechanism of the A-alloy compared with the B-alloy, an alloy without graphite but with a similar composition to that of the A-alloy. The form of the stress-strain curve shows the usual form with work hardening occurring at temperatures below 673 K; however, on the stress-strain curves at temperatures above 773 K, the maximum compression stress is reached at an early stage of deformation followed by a gradual decrease in the stress. The maximum compression strength of the A- and B-alloys at room temperature are approximately 2200 MPa and 2400 MPa respectively and decrease to about 1300 MPa at a temperature of about Tm/2 (700 K) on both alloys. The maximum compression strength of the A-alloy is slightly less than the B-alloy throughout all test temperatures. However, the strain rate dependence of maximum compression strength appears at temperature above 773 K on both the A-alloy and the B-alloy, that is, the strain rate sensitivity (m-value) can be obtained from the slope of linear relationship between ln σ_B and ln \dotε at each temperature; namely, m=0.03 at 773 K, m=0.08 at 873 K, and m=0.14 at 1023 K. Compressive failure is initiated by the deformation of graphite on the A-alloy, whereas on the B-alloy compressive failure is initiated by the crack of eutectic carbide caused by deformation of the large size matrix near the carbide. Therefore, it is presumed that in both alloys the compressive strength is maintained by the eutectic carbide, and their high-temperature deformation behavior is governed by the deformation of matrix.