The regulation of sulfate irons in concrete was determined by spectrophotometer under different conditions, and the comparison between dissolve acid method and weight method was used to determine sulfate irons in this paper. Results show that if the volume of solution is the same, sulfate ions content in concrete decreases with the increase of sample quality, and stabilizes finally. If the sample quality and the volume of solution is the same, sulfate ions content in concrete increase with the increases of temperature, and stabilizes finally. If the soak period is the same, sulfate ions content in concrete gradually become stable. Results show that the sulfate ions content in concrete approximately follow linear distribution by use of spectrophotometer method and the weight method.