To examine the efficacy of early intervention (4 weeks before pollen dispersal) with sphenopalatine ganglion (Xinwu acupoint) stimulation in patients with allergies after the onset of seasonal allergic rhinitis (SAR).This is a prospective, randomized and unblinded half-open study. Forty-one SAR volunteers were randomly assigned to either the sphenopalatine ganglion (SPG) acupuncture plus supplementary acupuncture (SPG group) or the sham-SPG acupuncture plus supplementary acupuncture (SA group) stimulation 4 weeks before the onset of allergy season. The changes of the total nasal symptom score (TNSS) and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores were measured on the first week in the onset of allergy season.Four patients dropped out due to local hematoma and pain in the SPG and SA groups. The remaining 37 patients continued through to the end of the trial. After early intervention 4 weeks before the onset of allergy season, the sneezing, nasal congestion and itchiness scores in the first week of onset time were significantly lower in the SPG group than in the SA group patients ( 0.001). The RQLQ score obtained at the onset of symptoms indicated that symptoms were more significantly ameliorated in the SPG group than in the SA group (0.001).The results of this study confirmed that early intervention by sphenopalatine ganglion (Xinwu acupoint) stimulation can effectively improve the symptoms and the quality of SAR patients' daily lives.