An optical detection apparatus for detecting a tissue comprises a housing, a detection unit and a processing unit. The housing includes a body portion and a detachable portion, the body portion has at least one first fixing structure, and the detachable portion has at least one second fixing structure which is cooperated with the first fixing structure. The detection unit is disposed within the housing, and includes at least one light emitting element and at least one light sensing element. The light emitting element emits a light entering into the tissue through the detachable portion, and the light sensing element receives the light exiting from the tissue. The processing unit is disposed within the housing and is coupled with the detection unit to analyze in accordance with the sensing signal.