The disclosure provides an electronic pen mainboard and an electronic pen. The electronic pen mainboard includes a mainboard ground, a ground line, a radio frequency signal feeder line, an antenna and a radio frequency chip. The antenna includes a radiating part distributed in an S shape; a ground part connected with the radiating part and connected with the mainboard ground through the ground line; and a transceiving part connected with the radiating part and connected with the radio frequency chip through the radio frequency signal feeder line. On a plane where the mainboard ground is located, the ground line is perpendicular to the radio frequency signal feeder line. The radio frequency chip is responsible for radio communication to realize remote wireless connection and control of each function; and the antenna is responsible for transmitting and receiving a radio signal.