In order to control the safety of R.C structure, the construction loads of multistory frame reinforced concrete buildings in xi’an were selected as the research objective. Based on the characteristic of construction loads, the survey on the work site had carried on during the construction progress. Variation of concrete dead weight had been discussed. And the mathematics models of live loads in different stages of construction process for reinforced concrete buildings were proposed through statistic analysis. The standard values of construction live loads were suggested at last.