Using a microcircuit fabricated on a diamond anvil cell, we carried out insitu conductivity measurements on β-boron at pressures up to 28GPa. The electrical conductivity of the sample increases with increasing pressure, but it does not return to original state when the pressure returns to ambient. As the conductivity gradually increases within a temperature region from 293 to 473K, two significant different conduction processes are observed. A possible reason for this result is proposed based on the valence band structure. In addition, by laser heating, our experimental result indicates that β-boron still shows the transport behavior of a semiconductor.