A method and system for quickly obtaining a median value is provided. The method includes such steps of carrying out the parallel processing, displacement and offset processing on the original data sequence with length N in turn, comparing magnitudes respectively, and taking Boolean value bit mosaic processing of comparison result as index address; using the generated lookup table to look up the table; determining a look-up table output value equal to (N-1)/2, and obtaining the data of displacement and offset processing corresponding to an input index address corresponding to the look-up tableoutput value, which is inversely transformed to obtain a median value result of the original data sequence and output to the outside. The invention is based on the parallel operation, and can quicklyobtain the median value result of the original data sequence.