Abstract: To cope with the problem that the existing tabular techniques based algorithms are unable to deal with large circuits in the polarity conversion, a fast conversion algorithm based on disjointed products is proposed.First the logic function is expressed as the form of the sum of disjointed products.Then by analyzing and improving the existing tabular techniques used for Reed-Muller functions polarity conversion based on maxterms, the proposed technique can convert the logic function from the form of sum of disjointed products into the XNOR/OR form with the fixed polarity directly.The proposed algorithm is implemented in C and tested under MCNC benchmarks.The experimental results show that, the proposed algorithm can carry out the polarity conversion fast for large circuits, and the conversion speed is less effect with the number of circuit inputs.