The invention discloses a sound activation detecting method and a sound activation detector, the core of which is: extracting the feature parameters of the current signal frame when the sound activation detection is needed; and determining the sound type of the current signal frame according to the feature parameters and the set parameter threshold. By the invention, the specific coding algorithm is not relied on when the used feature parameters in the classifying process are extracted, thus being convenient for maintenance and updating, and classifying the input signals into more sound types. When being used in the sound coding technical field, the invention can not only be used as new-opened variable rate sound frequency coding algorithm and standard rate selection foundation, but also provide foundation of rate selection for prior variable rate voice or sound frequency coding standard without VAD algorithm. The invention can be applicable to voice boosting, voice recognition, recognition of spoken person and other voice signal processing fields with strong commonality.