Abstract: The high-temperature mechanical properties of the low-alloy steel 12Cr1MoV during continuous casting were tested on a Gleeble-1500 thermal simulator within the temperature range from mold to outlet rollers. As a result, the plastic flow and strength and thermal plasticity curves at different strain rates from 600°C to peak temperature were given, with fracture morphology of specimens observed at different temperature. The test results showed that the ZST and ZDT of the steel are 1425°C and 1400°C, respectively. The percentage reduction of area of the tested steel is greater than 60% within the range from 1100°C to 1300°C, thus showing that the steel has higher resistance to high-temperature cracking. Its brittle temperature range is 1350°C to melting point and below 900°C.