Functionalization of mesoporous silica foam (MSF) is a feasible strategy to enhance the electrocatalytic performance of designed sensors. Herein, an organic ligand, pyrene-1-carboxaldehyde hydrazone (PCH), is used to functionalize MSF and as a modifier for carbon paste electrodes to construct a Cu2+ detection sensor. The experimental results demonstrate that the PCH functionalization can significantly enhance the sensor's sensitivity and selectivity. Under optimized conditions, the linear range of the prepared electrochemical sensor are 0.0050–1.0 μM and 1.0–10 μM, and the Cu2+ detection limit is 0.0020 μM. The developed sensor is applied to detect Cu2+ content in standard rice control samples, and the obtained results fall well within the range of marked values. Moreover, the recoveries of the standard addition method are 98.4–102.6 %, suggesting the developed sensor's good accuracy and practicability.