This paper presents a method for measuring the creep stress exponent of Ti6Al4V alloy in room temperature using nanoindentation with constant . As to find out the effect of the loading rate and the maximum load to the result, the diamond Berkovich indenter was loaded to different maximum loads with different loading rates, then the maximum load was held as a constant for 5 minutes, and the stress exponent of the material in room temperature was discovered based on the relationship between the indentation strain rate and the hardness during the hold period. It shows that the effects of the loading rate and the maximum load are so small to the result that they can be ignored, and the creep stress exponent of Ti6Al4V in room temperature got from the experiment is between 7.0513~7.216.