The reaction products in the process of boron isotope separation by multiphoton absorption of BC13 have been studied. When oxygen was used as a scavenger, the stable solid product was B2O3, and (BOC1)3 was not found. Our experiments show that when irradiated with focused TEA C02 laser, BC13 reacted with fluoroearbou grease to form boron fluoro-chloride and boron trifluoride. A possible mechanism for the reaction between BC13 and fluorocarbon grease has been proposed. It seems that BC13 was first dissociated into BC12 and Cl by intense IR laser action, and BC12 then reacted with fluoroearbon grease to form BFC12. Moreover BP2C1 and BF3 were formed because of the dismutation of BFC12.