<p>Heavy metals ions are typically detrimental to environment and human health. In this work, an electrochemistry sensing platform for simultaneous detection of lead ions (Pb²⁺) and cadmium ions (Cd²⁺) was constructed by integrating the DNAzyme catalytic amplification signal technology and the aptamer conformational change strategy. The gold nanoparticles (AuNPs) were loaded onto 2D Ti₃C₂ MXene nanosheet to construct electrode substrate material (Au@MXene), electrochemical tests indicated that the Au@MXene nanocomposite could effectively enhance the electron transfer efficiency and electrochemical activity of the electrode. Methylene blue (MB) and ferrocene (Fc) were used as redox indicators, a dual signal response system was constructed to achieve selective detection of Pb²⁺ and Cd²⁺. In the presence of Pb²⁺, the DNAzyme catalytic cycle was activated, resulting in continuous release of methylene blue-labeled catalytic chains (Z2) from the electrode surface and the MB response decreases. In the presence of Cd²⁺, the ferrocene-labeled aptamer (CAPF) was predisposed to form a Cd²⁺-CAPF complex. The combination of CAPF and Cd²⁺ induced a conformational change of the complex into a hairpin structure, leading to a significant enhancement of the Fc signal. Notably, the constructed dual signal response aptasensor effectively avoids signal interference in the complex environments, and can detect Pb²⁺ and Cd²⁺ both independently and simultaneously. Under optimal conditions, the limits of detection (LOD) of this sensor were 3.33 × 10⁻⁵&#xa0;<i>μ</i>M (Pb²⁺) and 5.69 × 10⁻³&#xa0;<i>μ</i>M (Cd²⁺), with high selectivity, reproducibility, and stability.</p>