The Physical random access channel (PRACH) of the fifth generation of mobile communication (5G) with a new radio-access (NR) is composed of cyclic prefix (CP) and preamble sequence. While the CP of PRACH guarantees sufficient length for full sequence detection to PRACH detector, it also hampers finding out the PRACH start point since the CP itself causes a considerable pseudo-peak at PRACH detection. Ruling out this pseudo-peak using threshold contains risk of mis-judgement depending on fading environment or PRACH searching time offset. In this paper, we propose a comprehensive PRACH detection procedure to find out PRACH sequence and the start point of uplink correctly.