In situ high-pressure energy dispersive X-ray diffraction experiments on natural tourmaline have been carried out using diamond anvil cell（DAC） device with synchrotron radiation source. The pressure dependence of the lattice parameters of tourmaline is reported up to 27.8 GPa at room temperature. In the experimental pressure range

we have not observed the evidence of phase transition for tourmaline. The Murnaghan equation of state is used to fit the P-V data

assuming the pressure derivative K’=4

then the isothermal bulk modulus K

298

=183.5±4.2 Gpa is obtained.