To resolve the problems currently existing in access protocol for Terahertz Wireless Personal Area Network (THz-WPAN) for PicoNet Coordinator (PNC) handover process, such as imperfect PNC handover process, redundant information transmission, waste of obvious timeslot resources, an access protocol of piconet coordinator high efficient handover for terahertz wireless personal area networks called PCHEH-AP (Piconet Coordinator High Efficient Handover Access Protocol) was proposed. By using deleting the specified node redundancy information mechanism, confirming first and handover next mechanism, PNC handover adaptive slot allocation mechanism, PCHEH-AP generally regulates the PNC handover process, improves channel utilization, reduces data delay, and makes PNC handover more reasonable and efficient. The simulation results show that compared with the protocol defined by IEEE 802.15.3c and the HTLL-MAC protocol, the data delay of PCHEH-AP is reduced by at least 8.98% and the throughput of MAC layer is also increased by 3.90%.