As widely used pharmaceuticals and personal care products (PPCPs), hydroquinone (HQ) and catechol (CC) pose a great threat to human beings and the environment due to their high toxicity and low biodegradability. Therefore, it is essential to detect them simultaneously and sensitively. In this study, a novel bifunctional ZIF-8/carbon black (CB) modified MXene (MXene/CB/ZIF-8/GCE) electrochemical sensor (ECS) based on a glassy carbon electrode (GCE) was constructed for simultaneous detection of HQ and CC by si-tu doping ZIF-8 on MXene/CB with a honeycomb sandwich structure. The unique morphology, structure and electrochemical properties of MXene/CB/ZIF-8 have been characterized by SEM, EDS, XRD, XPS, CV, EIS and DPV. CB was introduced into MXene with an unique accordion-like structure to prevent the buildup of MXene interlayers while enhancing its electrical conductivity, and ZIF-8 provided abundant adsorption active sites to facilitate charge and ion transport, and the three exerted a synergistic effect to form an excellent electrode material with ultra-large specific surface area and superior electrical conductivity. The results displayed that the constructed sensor exhibited outstanding sensing ability for the HQ and CC with a wide linear range (0.3-160.0 μM for HQ and 0.5-165.0 μM for CC) and low limits of detection (LODs) (0.0126 μM for HQ and 0.0082 μM for CC). Besides, the sensor had ideal anti-interference ability, reproducibility, and stability, and the simultaneous detection of HQ and CC in environmental water samples could be realized with satisfactory, which demonstrated great potential for monitoring ecological water samples in practice.