The phase transformation between cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) from the c-BN nanocrystals synthesis by pulsed laser induced liquid-solid interfacial reaction (PLIIR) was studied by calculating the probability of phase transition of the h-BN structure over a potential barrier in boron nitride equilibrium phase diagram. Consequently, we found that the probability of phase transition from h-BN to c-BN goes up to 10(-5)-10(-4) in the pressure-temperature region of 5-6 GPa and 2500-3500 K created by PLIIR. Furthermore, the probability distribution of the phase transition from h-BN to c-BN was obtained in the corresponding pressure temperature region, and the dependence of phase transition probability on temperature was found to be in agreement with the Arrhenius rule. (C) 2003 Elsevier Science B.V. All rights reserved.