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