Here, for the first time, the direct and indirect mechanism is reported for nickel phosphate (nNiPh) modified glassy carbon electrode (GC) in alkaline solution. The two mechanisms are discussed using formaldehyde (FAL) electrochemical oxidation as the probe reaction. At lower FAL concentration, the indirect mechanism exists while at higher FAL, the direct mechanism prevails. Gradual conversion from indirect to direct mechanism is observed with the [FAL]. The results are analyzed to explain both mechanisms are given here. Different surface and structure characterizations are characterized by different techniques including BET surface area determination, TEM, FE-SEM, and XRD.