This paper presents the results of an experimental and statistical study on the effect of high temperatures on the retained mechanical properties of high-strength concretes (HSC). The mechanical properties of HSC significantly change during and later than exposure to elevated temperature. The compressive and splitting tensile strength of more than 400 HSC cylindrical specimens with sixteen mix proportion have investigated to study the effect of mix proportion on the retained mechanical properties of HSC specimens after heating. According to these results, a considerable loss was observed for all mixes and specimens in strength particularly in tensile splitting strength. In addition, these experimental data were investigated using Taguchi approach to find the effective parameters of mix proportion. Also, the most optimum mix proportion was found and checked experimentally. According to our results, by controlling some factors in the mix proportion, it is possible to reduce the retained destructive effects of elevated temperature on HSC specimens.