To make up for the limitations of renewable energy sources like solar and wind power, more stable operation at elevated temperature in future power plants will inevitably be demanded. These operating circumstances lead to the accumulation of time-dependent deformation at elevated temperatures. For crucial parts of power plants, ferritic and austenitic stainless steels are typically used. For use in cutting-edge steam boilers and other critical components, stainless steels Sanicro 25, Sanicro 28 [1] and Alloy 27Cr33Ni3Mo are important materials candidates with excellent high-temperature capabilities. In order to evaluate the short-term creep performance of the three stainless steels, the materials were subjected to various strain rates from 1×10-3 /s to slow strain rate tensile (SSRT) regime of 1×10-4/s, 1×10-5/s, and 1×10-6/s at 650 °C. For comparison, load-controlled creep testing was performed at the identical temperature of 650 °C under high, intermediate, and low applied stress conditions. At 650 °C, similar corresponding flow stress behaviors remained under various strain rates. However, the elongation at fracture decreases with the decreasing strain rate. Fractographic examination reveals that intergranular cracking dominates the fracture process. The correlation between displacement-controlled SSRT and load-controlled creep testing is discussed.