The invention discloses a sulfo-functional-group-contained polymer microporous separator used for a lead storage battery. The sulfo-functional-group-contained polymer microporous separator comprises the following components in parts by weight: 30 parts of polymer base material, 25-35 parts of polymer material with the sulfo functional group, 30-40 parts of extending oil, 3 parts of antioxidant and 2 parts of additive. The polymer material with the sulfo functional group is combined with the polymer base material to prepare the polymer microporous separator which is widely applicable to the lead storage battery; and due to the intermolecular force between the sulfo functional group (-SO<3>H) and sulfuric acid in an electrolyte solution, the fluidity of the electrolyte solution is improved, the concentration polarization phenomenon of the lead storage battery is effectively relieved, the fluidity of the sulfuric acid electrolyte solution is improved, the utilization rate of the active material of the polar plate is improved, the capacity of the battery is increased, and the cycling life of the battery is prolonged.