Electrorheological (ER) effect of ultrathin titanium dioxide (TiO₂) nanorods solutions in different solvents was investigated. TiO₂ nanorods were synthesized and dispersed in raw suspension, Octadecene (ODE) / Oleylamine (OLAM), and hexane/ OLAM, respectively. Hybrid microfluidics with integrated microelectrodes were successfully fabricated to characterize the ER effect of these minute nanorods solutions. We showed, for the first time, that the TiO₂ nanorods in ODE/OLAM have the best ER effect in microchannel without clogging problem. The corresponding viscosities at different electric fields were also calculated.