Based on the micro-financial perspective of optimizing householdresource allocation, combined with Becker’s family theory, this paperexamines the impact of broader access to credit and capital marketon household decisions with respect to the number of children by constructinga revised four-period life cycle model. The results show thatloosening borrowing constraints significantly promotes the fertility rate,while opportunities for financial investment inhibits the fertility rate.We find that disposable income weakens the direct positive impact ofcredit quota and promotes the direct negative impact of on fertility.The excessive consumption of households strengthens credit constraintsand encourages household consumption, which accelerates a crowdingout effect on fertility. In addition, endowment insurance prompts households’investment in the capital market, which suppresses reproductivebehavior.