The present disclosure relates to a multi-functional adapter clip including a receptacle which is provided with an insertion interface capable of inserting therein a banana plug electrode, a fastening hole capable of fastening a stud electrode, and a clamping portion capable of clamping a sheet electrode. It adopts upper and lower plastic cases, a spring, and metal elastic pieces. The adapter clip can be connected with ϕ 4.0 mm banana plug electrode or a ϕ 3.0 mm pin electrode. It can also be connected with ϕ 4.0 mm stud electrode and can be used as a clip-on electrode. After the clamping portion is clamped together, a boss of the upper plastic case is moved by tension of the spring and pushes a narrow waist portion of the stud electrode into a U-shaped groove in the lower plastic case to lock the stud electrode.