Arexperiment was carried out for the analysis of time-varying regularity of early-age concrete strain under the influence of free air temperature changes. The strain data and the weight of specimens were collected. It is found that the severe shrinkage of early age (≤3d) concrete appears in the course of heating and cooling of daily temperature. And the magnitude of the severe shrinkage is 100×10 -6. The expansion strain difference is up to 100×10 -6 for different water cement ratio concrete, and the shrinkage strain difference is up to 200×10 -6.