Abstract: The relationship of V/W-R is presented by a nomograph which is of general application, for example, in potency bioassay. It simplified the currently used 'twoor three-doset method which involves complicated calculations.The proposed nomograph can be applied to bioassay, potency assay of antibiotics etc. According to the specific requirements, general nomographs of different precision may be made which, if drawn correctly, will indicate values coincide well with the calculated ones.