The Pb-Al alloy, which undergoes liquid-solid (L-S) phase separation, can potentially serve as a high-performance and low-cost anode material for hydrometallurgy and a grid material for lead-acid batteries. For this purpose, a microstructure containing uniformly dispersed micro/nano Al-rich particles in the Pb matrix is desired. However, during cooling of the Pb-Al alloy melt, Al-rich particles nucleate from the matrix melt first, grow, and migrate in the melt until they are caught by the solidification interface. Consequently, Pb-Al alloys often exhibit a solidification microstructure with coarse Al-rich particles or significant phase segregation. Recent studies have shown that the application of electric current pulses (ECPs) during solidification can effectively modify the microstructure evolution. This research aims to investigate the possibility of controlling the L-S phase separation process and microstructure of Pb-Al alloys. To achieve this, continuous solidification experiments were carried out on Pb-Al L-S phase separation alloy while subject to ECPs. A theoretical model describing the microstructure formation during the L-S phase separation process of the alloy under the effect of ECPs was proposed. The microstructure evolution was simulated according to the experimental conditions, and the effect of ECPs on the L-S phase separation process of the alloy was analyzed. It was demonstrated that ECPs can effectively reduce the energy barrier for the nucleation of Al-rich particles during the L-S phase separation process of Pb-Al alloy, enhance the particles' nucleation rate, and reduce the average radius, thereby promoting the formation of a composite containing in situ micro/nano Al-rich particles embedded in the Pb matrix. The peak current density (j_max) has two critical values (j_{\mathrm{c}\mathrm{1}} and j_{\mathrm{c}\mathrm{2}}). When j_{\mathrm{m}\mathrm{a}\mathrm{x}}\le j_{\mathrm{c}\mathrm{1}}, ECPs have a negligible effect on the nucleation behavior of Al-rich particles. When , the nucleation rate and number density of the Al-rich particles increase rapidly with increasing j_{\mathrm{m}\mathrm{a}\mathrm{x}}. When j_{\mathrm{m}\mathrm{a}\mathrm{x}}\ge j_{\mathrm{c}\mathrm{2}}, the nucleation rate and number density increase continuously with increasing j_{\mathrm{m}\mathrm{a}\mathrm{x}}, but at a lower rate. Furthermore, the electromagnetic force causes migration of the Al-rich particles toward the center of the sample, resulting in the emergence of an Al-poor layer on the surface of the sample and promoting the formation of a special composite composed of a Pb-rich shell and an in situ Al-rich particles reinforced Pb matrix core.