Nano-boric acid is being used in traditional lubrication oils due to providing low friction coefficient while it is friendly to environment. Also, recently it is shown that it improves motor performance when used in diesel fuels. In this study, growth mechanism of nano-boric Structures were investigated and characterized by SEM and XRD. In the first stage bamboo shaped hollow structures (length: 25 pm, diameter: 1 mu m, wall thickness less than 10 nm) are formed. By boric acid transfer in time, hexagonal like head (diameter: 5 pm, wall thickness: 25 nm) emerges and the shape becomes like a tadpole. After that growing occurs in 3-D and hexagonal head grows in bowl form, with nucleation of new particles (d: 10 nm) inside. Finally, bowl-shaped structures are closed and coalesced.