In order to study the kinetics of carbon plasma under different air pressure conditions, the carbon plasma is diagnosed by optical emission spectroscopy. The carbon target is ablated with a 1064 nm Nd∶YAG laser. The early emission spectrum is continuous spectrum, and the electron temperature of the carbon plasma is estimated by using the black body radiation formula. When the line spectrum appears, the electron temperature is calculated by Boltzmann mapping method, and the evolutions of electron temperature and density with time and the influence of different pressures on the evolutions are observed. The results show that the changes of the temperature and density of electrons are consistent with time under different air pressure conditions. And as the gas pressure increases, the plasma is limited. As the collision between particles increases, the electron temperature and electron density increase. Graphene films are deposited at pressure of 0.01 Pa.