► The citrate precursor synthesized in leaching process is Pb(C 6H 6O 7)·H 2O. ► Orthorhombic lead oxide, Pb and amorphous C are the major calcination products of the Pb(C 6H 6O 7)·H 2O in nitrogen gas. ► Nanostructured leady oxide powders are obtained at 370 °C for 20 min calcination in air. As part of contribution for developing a green recycling process of spent lead acid battery, a nanostructural lead oxide was prepared under the present investigation in low temperature calcination of lead citrate powder. The lead citrate, the precursor for preparation of this lead oxide, was synthesized through leaching of spent lead acid battery paste in citric acid solution. Both lead citrate and oxide products were characterized by means of thermogravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The results showed that the lead citrate was sheet-shape crystal of Pb(C 6H 6O 7)·H 2O. When the citrate was calcined in N 2 gas, β-PbO in the orthorhombic phase was the main product containing small amount of Pb and C and it formed as spherical particles of 50–60 nm in diameter. On combusting the citrate in air at 370 °C (for 20 min), a mixture of orthorhombic β-PbO, tetragonal α-PbO and Pb with the particle size of 100–200 nm was obtained, with β-PbO as the major product. The property of the nanostructural lead oxide was investigated by electrochemical technique, such as cyclic voltammetry (CV). The CV measurements presented the electrochemical redox potentials, with reversibility and cycle stability over 15 cycles.