The resistance properties of gassolid twophase flow in branch pipe are expatiated.The pneumatic conveying experiments for sand with average particle diameter 0.25 mm and 0.5 mm are carried out by using compressed air in horizontal Tbranch pipe.The results show that under the condition of the systemic operation pressure keeping to a constant value,when the conveying velocity gradually descends,the unit length pressure drop of the branch pipe gradually declines at first,however when the conveying velocity reduces to some extent,the pressure drop descends slowly,sometimes the pressure drop even begins to rise.When the difference value of the flow valve opening degree of the respective pipe is raised,the critical velocity of the respective branch pipe changes in reverse direction.Under the experimental condition of the paper,the less average diameter particle is,the higher the critical velocity is.