The invention provides a cognitive radio spectrum sensing method, belongs to the technical field of cognitive radio and relates to a rapid CUSUM detection technology. According to the cognitive radio spectrum sensing method, by further improving and applying a non-parameter CUSUM detection algorithm to spectrum detection, the shortcomings of an existing rapid detection method can be overcome under the conditions that no signal priori knowledge exists and signal appearing moment is random, and signals can be rapidly detected. The cognitive radio spectrum sensing method can dynamically adjust offset according to the detection situations and further shorten detection delay.