ZnO Calthrop-like framework have been synthesized via a microwave assisted way by thermal decomposition of precursors in the ionic liquid 1-butyl-3-ethyl imidazolium tetrafluoroborate ([Beim]BF4) aqueous solution. The structure of [Beim]BF4 were analyzed by means of IR and 1HNMR, The as-samples were characterized by XRD, SEM and UV techniques. The results showed that the as-prepared ZnO have wurtzite structure. nanorods have a diameter of 50 nm to100 nm and lengths of about 3 μm , and the ionic liquid [Beim]BF4 can not only act as a reaction medium but also modify ZnO nanorods in the reaction. The growth mechanics of ZnO nano-structure was preliminary studied.