A modularized probe head for high frequency probing is provided. The probe head mainly includes a probe head, a mounting board and an interposer between the probe head and the mounting board. The probe head has a plurality of cavities on its back surface. A plurality of decoupling components are installed inside the cavities and are electrically coupled to the ground/power circuitry of the probe head via by-pass circuitry. The interposer has a bottom surface corresponding to the back surface of the probe head, and includes a plurality of contact ends on the bottom surface. Some of the contact ends electrically contact the decoupling components and electrically coupled to the ground plane of the mounting board.