Rheological property is one of the most important mechanical properties of rock. Great importance shall be attached to long-term strength of the rock among mechanical properties in most geotechnical engineering

while the present study of it is asymmetrical compared with the creep property. Creep test is the most common and practical way to confirm long-term strength of rock. Based on uniaxial compression creep test of red sandstone rock in the CSS-2950 biaxial rheological testing machine; theory accuracy and operability of transition creep and isochronous curve methods are discussed in the research of testing long-term strength of the rock. Meanwhile

a new method to confirm long-term strength of the rock is proposed; and the time for rock to be destroyed under load is predicted by the combination of creep curve and stress-strain curve. The results show that the combination of creep curve and stress-strain curve plays a leading role in the confirmation of long-term strength of the rock in geotechnical engineering field.