The invention provides a special burst detection method and device. TFCI identifiers, SS identifiers and TPC identifiers in joint detection output data of current subframes are eliminated, and preprocessing data of the current subframes are obtained; the average values of all kc symbols in the preprocessing data are accumulated, decision factors are obtained, and the kc shows the number of imaginary codes; greater values in real-part absolute values imaginary-part absolute values of the average values of all the kc symbols in the preprocessing data are obtained, the accumulated values of the greater values are multiplied by preset judgment thresholds, and real-part reference values are obtained; when the imaginary absolute values of the decision factors are less than differences of the rear part values and the real-part reference values, the fact that the current subframes are SB is determined. By adopting the special burst detection method and device, detection of SB with reduced emitting power can be achieved.