An ultrasonic instrument includes a socket and a front-end system, wherein the socket is provided with at least two probe model identification pins and a plurality of functional signal pins. The front-end system comprises a decoding module, a switch selection module, and a probe driving control module. The decoding module has its input terminals electrically connected to the probe model identification pins of the socket, and has its output terminal coupled to the control terminal of the switch selection module. The input terminals of the switch selection module are electrically connected to the functional signal pins of the socket respectively, and in response to a probe identification signal outputted from the decoding module to the control terminal, the switch selection module establishes connection between its input terminals and a group of output terminals corresponding to the probe identification signal. The probe driving control module is electrically connected to the output terminals of the switch selection module.