The time-of-flight mass spectrum of freon F-113 (C2F3Cl3) has been obtained by other researchers′ experiment under action of a 800 nm sapphire femtosecond laser, and three major dissociation channels of C2F3Cl+3 are discovered by calculating the proportion of each peak in the mass spectrum and analyzing the detected fragment ions. The energy difference of each dissociation channel is calculated and the chlorine isotope abundance ratio of major ions in the mass spectrum approaches the natural abundance ratio of 3.13. Stable configurations of major ions in the C2F3Cl3 light dissociation process are obtained by the optimization at B3LYP/6-311G++(d,p) basis set level of Gaussian 09. The infrared spectrum and single point energy of each configuration are obtained through calculation of frequency and energy. The potential energy surface scan on stable configurations of C2F3Cl3 and C2F3Cl+3 obtained by the optimization at B3LYP/6-31G++(d,p) basis set level of Gaussian 09 shows that the activity of C—C (1-2) and C—Cl (2-3) bonds is stronger than that of C—Cl (1-5) and C—F (1-7,1-8,2-6) bonds in C2F3Cl+3. C—C (1-2) and C—Cl (2-3) bonds are easy to break and dissociate, which is in coincidence with the strongest or stronger peaks in the mass spectrum obtained by the experiment.