Abstract: To assess the slope stability after underground and open-pit mining in synergy in Shizhuyuan Polymetallic Mine,a thorough understanding of geological conditions and rock mechanical parameters is necessary.By carrying out the uniaxial compressive strength test,splitting tensile test,and shearing test,the mechanical property and parameters of standard specimens are measured including compressive,tensile,and shearing strength,as well as cohesiveness,internal friction angle,and elastic modulus.Given the subjective and fuzzy problems existing in the traditional rock mechanical parameter reduction,a fuzzy mathematical method combining indoor rock specimen test and engineering geological data is used for the reduction,obtaining the rock mechanical parameters that are reasonable and accurate and can be applied in actual engineering analysis and modeling calculation.