The experiments on probability distribution of compressive strength of high strength concrete and normal strength concrete were carried out in this study. Shape of probabiliry distribution of compressive strength class of any kinds of concrete were definied normal distribution, theoretically, in quality control. It is clear that the peak of distribution is higher than mean value of strength in high strength concrete, nevertheless the mean value is equal to the peak of distribution in ordinary strength class of concrete. This means the probable minimum would be lower than the specified minimum , make the strength fall below the design strength in high strength concrete.
