Abstract: In this work, multi-walled carbon nanotubes (MWCNTs) and poly(2-amino-5-mercapto-1,3,4-thiadiazole) (PAMT) were modified on the surface of a glassy carbon electrode to form a composite film via electrodeposition way. The electrochemical property of the prepared MWCNTs/PAMT composite film electrode was characterized by cyclic voltammetry and AC impedance. Subsequently, it was employed to perform simultaneous detection of trace Cd²⁺ and Pb²⁺ in water. According to the results, Cd²⁺ and Pb²⁺ are capable of generating two independent differential pulse signals on the electrode, and the signal intensity is proportional to the concentration of the targets. Under the optimal conditions, the detection linear range is from1.0 to 150 μg/L for Cd²⁺, and that is from 2.0 to 200 μg/L for Pb²⁺, and the corresponding detection limit is 0.4 μg/L and 0.3 μg/L, respectively. The reproducibility assays display that the RSD of the six detection results of Cd²⁺ and Pb²⁺ are 3.4% and 5.6%, respectively. Meanwhile, anti-interference assays show that the composite membrane electrode possesses a high selective response to Cd²⁺ and Pb²⁺. To sum up, the prepared MWCNTs/PAMT composite film electrode owns a promising application prospect forthe simultaneous detection of trace Cd²⁺ and Pb²⁺ in water.