As the height of the constructed rock-filled concrete (RFC) dam continues to increase, higher requirements are put forward for the performance indicators of the dam. To understand the actual compressive behavior of RFC dams, indoor laboratory tests on the compressive performance of RFC at engineering scale (side length of 900 mm or above) were carried out. In this paper, cubic specimens of self-compacting concrete (SCC) and RFC with a side length of 900 mm were made, and the laboratory test method of compressive properties of RFC at engineering scale was explored. The results show that it is feasible to make cubic specimens with a side length of 900 mm using the mould made of steel plate with a thickness of 10 mm. Both SCC and RFC cubic specimens showed “X”-shaped failure pattern, and there were three types of failure in RFC cubes, namely the failure of SCC, the failure of SCC and rockfill interface, and the failure of rockfill. The compressive strength of RFC and SCC cubic specimens with a side length of 900 mm was 76% and 67% of that of standard cubic specimens respectively; however, that of RFC cubic specimens was 12.50% higher than that of SCC cubic specimens. This indoor test method not only enriched the test data of RFC at engineering scale, but also provided a reference for subsequent mechanical tests as well as the design and construction of rock-filled concrete dams.