Effective antigen delivery and immune stimulation in nasal mucosa determine the success of mucosal immunity. Here, an oil-in-ionic liquid (o/IL) nanoemulsion formulated with choline and niacin IL ([Cho][Nic]), squalene, and Tween 80 surfactant is explored as a vaccine delivery system for intranasal mucosal immunization. Compared to the o/w emulsion counterpart without the ILs, the o/IL manoemulsion showed a reduced and more uniform size of approximately 168nm and significantly improved stability. Studies in mice model showed that when was used as an intranasal vaccine delivery system for influenza split-virus antigens, the antigens in the o/IL nanoemulsion induced strong mucosal immune responses with secretory IgA titers 25- and 5.8-fold higher than those of naked and commercial MF59-adjuvanted antigens, respectively. The o/IL nanoemulsion system also induced stronger systemic humoral responses. The excellent mucosal adjuvant effects of the o/IL nanoemulsion mainly benefited from the prolonged retention of antigens in the nasal cavity, enhanced antigen permeation into the submucosa, and the consequently promoted proliferation of CD11b cells and CD4+ T cells in nasal mucosa-associated lymphoid tissue. Moreover, when used as an injection adjuvant, the o/IL nanoemulsion also induced stronger humoral immune responses than MF59. Thus, the [Cho][Nic]-based o/IL nanoemulsion vaccine delivery system can serve as a promising adjuvant platform.