Abstract: The proppant pack conductivity is one of the most important parameter for fracturing design,frequently obtained from standardized API conductivity test.However,well test and production data analysis shows large difference between the experimental data and realistic condition,which impart significant influence on the efficiency of fracturing stimula tion.A systematic experiment study was conducted on non-Darcy and multiphase flow effect which are two important factor affect the proppant pack conductivity.Different parti cle size,closure stress,type of proppant and water satura tion are all taken into account in studying non-Darcy and multiphase flow effect.Study indicated that,non-Darcy effect are affected by porosity,permeability of prpppant pack,and roundness,angularity,roughness,size distribu tion of proppant;multiphase flow effect are affected by wa ter saturation and permeability.Non-Darcy flow effect made the permeability loss one times,multiphase flow effect made the permeability decrease nearly six times,whereas combining the two kinds of effect made the permeability de crease an order of magnitude.Therefore,there must be a clear understanding of the true conductivity of pack before fracturing design.Only in this way can get better fracturing effectiveness.