It proposed a pinhole-coupled dual-channel terahertz waveguide directional coupler. It adopts a novel ladder structure and combines two single-channel couplers to achieve the same coupling output in two channels. The research results show that in the frequency range of 180-260 GHz, the coupling degree of the coupler is 10 dB, the maximum output error is less than 1.6 dB, the return loss is greater than 25 dB, the isolation is greater than 35 dB, and the relative bandwidth is 36%. Compared with the traditional terahertz waveguide directional coupler, the coupler can realize dual-channel coupling output, and can be used for dual-channel power detection, power synthesis and distribution in terahertz systems.