The solvothermal reactions of Ti(O
i
Pr)
4
in alcohol using ionic liquid as additive were investigated. In the presence of [BMIM][Cl], [BMIM][Br], [BMIM][NTf
2
], [BMIM][SO
3
Me], [BMIM][SO
4
Me], or [BMIM][OTf] (BMIM = 1-Butyl-3-methylimidazolium), pure anatase nanoparticles were obtained. The controlled hydrolysis of Ti(O
i
Pr)
4
in the presence of ionic liquids to form titanium oxo clusters plays a key role in the formation of anatase nanostructures, and ionic liquids can be repeatedly used to synthesise anatase nanoparticles. However, in the presence of [BMIM][PF
6
], [BMIM]
2
[Ti(OH)
6
] was obtained by an anion exchange reaction.