Double sampling plan is an examination with a certain parameter, so it cannot decide about manufactured products whose portion parameter is not certain. The main goal of this survey is to introduce double variable plan when  is indefinite to examine manufacturing products when concerned characteristics are normally distributed. Plan parameters are achieved by an optimization manner. Sum of fuzzy customer and producer’s risks and contract’s commitments are assumed as a goal function and restrictions, respectively, in this manner. Optimum values of parameters are provided to be employed in industry for variant compositions of demands. A simulation study is also conducted to represent that the presented approach becomes traditional one as  is not imprecise. In addition, conclusions display that the proposed method is more economical than the existing scheme. At the end, an industrial example is given in real situations.