Abstract: Based on the analysis of the changes in the pertinent regulations of the standards concerned and the existing experimental results,the conversion relations between axial compressive strength and cubic compressive strength;between direct tensile strength and cubic compressive strength of lightweight aggregate concrete were deduced.According to the mathematical model of probability density function of random variable _c,the statistical parameters of the strength of lightweight aggregate concrete were obtained in the light of computation rules of the statistical parameter of random variable function.On the basis of the statistical parameters and the definition of characteristic value of material strength,the standard values of axial compressive strength and direct tensile strength of lightweight aggregate concrete were acquired.