Abstract: In order to study the sensitivity of factors influencing the width of fractured zone of strip pillar,and regarding the V3 ore body as an object of investigation in Shanghengshan Mine,there are some these that are selected as main controlling factors,such as the mining depth,seam thickness,strip mining width,mechanics parameters of ore body and dip angle of ore body.21 different simulation test plans were designed.Many a different numerical model was built with kinds of simulation test plans,and extracted the deposit models.The Mohr Coulomb yield approach index(YAIm-c) function was written by fish language in FLAC^3D,which was applied to calculate the width of fractured zone of strip pillar.The rupture zone width of calculated results were dealt with orthogonal analysis of variance show that the mining depth has a significant influence and strip mining width,seam thickness have non-significant influence on the width of fractured zone.In rock mass mechanics parameters,tensile strength displays significantly,and cohesion,internal friction angle show not.The results show that the sensitivity sequence of influencing factors is as follows：tensile strength,internal friction angle and cohesion.The study shows that mining depth has the direct influence and tensile strength has the inverse influence on the width of fractured zone.The results of the study have important engineering significance to estimate the width of fractured zone and safely evaluate pillar stability.

Key words: Width of fractured zone of strip pillar, Sensitivity, Orthogonal analysis of variance, Main controlling factors