Abstract: By the cyclic loading and unloading tests on concrete under the conditions of different lateral pressures, making analysis of the enfluences of the lateral pressures and the strain rates on the hysteresis loop area in the stressstrain curve and presenting a simplified statistic method in analyzing the hysteresis loop area based on the stressstrain curves, the relationships between the hysteresis loop area and the cycle number were established in this study. It is found from the analysis results that the dissipation energy of an unit volume of the concrete increases firstly with the increase of the number of cycles and then decreases, and the maximum value of the dissipation energy of an unit volume is closely related with the peak strain. The dissipation energy of an unit volume has an obvious lateral stress sensitivity during the cyclic loading and unloading process. A fitting analysis of the relationships between the dissipation energy and the number of cycles in the process of the cyclic loading and unloading on the concrete specmens was carried out by use of the Weibull statistical model. The calculated results show that the hysteresis loop area and the number of cycles in the cyclic loading and unloading under the different lateral pressures obey the doubleparameter Weibull model distribution.