Lead (Pb) is a heavy metal environmental pollutant that can cause functional damage and anemia of immune organs. More and more evidence indicate that the toxicity of lead was related to apoptosis driven by oxidative stress and endoplasmic reticulum stress. This article mainly discusses the protective effect and mechanism of folic acid intervention on lead-induced spleen injury and apoptosis. In this study, Sprague-Dawley rats were randomly divided into control group, lead exposure group (0.2% lead acetate), folic acid + lead group (0.4 mg/kg folic acid and 0.2% lead acetate), and folic acid group (0.4 mg/kg folic acid). By recording and calculating the rat’s initial body weight, final body weight, net weight gain, daily weight gain, and spleen index, observe the rat’s weight change and spleen weight. And adopt the immunofluorescence staining method to determine the expression level of NrF2, HO-1, GRP78, CHOP protein in the spleen. The results showed that The 0.4 mg/kg folic acid diet did not significantly improve in the body weight and spleen index of lead-exposed rats (P > 0.05). While compared with the control group, the expression levels of HO-1 and CHOP protein were significantly increased in the lead exposure group (P < 0.05), and the expression levels of HO-1 and CHOP protein were significantly reduced in the folic acid intervention group (P < 0.05). In conclusion, lead exposure increased the expression levels of HO-1 and CHOP in the spleen of rats, and caused damage to the spleen. Folic acid down-regulated the expression levels of HO-1 and CHOP proteins through the two pathways of NrF2/HO-1 and GRP78/CHOP, thereby exerting a certain protective effect and alleviating the spleen caused by lead-induced oxidative stress and endoplasmic reticulum stress damage.