A granisetron hydrochloride selective electrode is prepared based on granisetrontetraphenylboron as a carrier . Orthogonal methodology is adapted for studying the impacts of active substance content and Plasticizer on response performance of PVC Membrane Electrode. The option of Granisetron hydrochloride Sodium Tetraphenylboron IonAssociation Compounds(4.8% in membrane) as active substance and Dinoctyl phthalate(DOP) as Plasticizer is the best scheme. A fast nearNernstian response is shown for granisetron of 5.0×10-2～1.0×10-5 mol·L-1 with the slope of 58.7 mV/decade. The detection limit is 8.0×10-6 mol·L-1 and the electrode can be used for potentiometric determination of granisetron hydrochloride tablets directly. The recovery range is 99%～102% which is in agreement with those determined by the method in the Pharmacopoeia.