With the increasing power densities of chip and diminishing size of semiconductor chips, thermal interface materials become a research emphasis to accelerate the development of semiconductor industry. Vertically aligned carbon nanotubes are good thermal interface materials because of high thermal conductance and excellent mechanical compliance. To reduce the thermal contact resistance between vertically aligned carbon nanotubes and silicon, thermocompression method in magnetic field was used to bond them in this work. The surface of vertically aligned carbon nanotubes was metallized with nickel and a vacuum chamber was used as bonding condition. The thermal contact resistance R_mc between vertically aligned carbon nanotubes and metallized Si of 12 sample groups were measured with a thermal transient tester. The result shows that the R_mc with magnetic field is 14% lower than the R_mc without magnetic field averagely. The magnetic field can be used to reduce the thermal contact resistance between vertically aligned carbon nanotubes and metallized Si.