We have analyzed the effects of the pairing force on the nuclear structure of light nuclei: F19-g24. It is found that with the coupling strength G, Gx A~16-18 Mev, the observed moments of inertia of these nuclei can be predicated very well. The estimated even-odd mass difference P in general is a little larger than the energy gap in light nuclei. The fluctuation of the number of particles △N~1-1.5. The neglected higher-order terms in Bogolyubov-Belyaev's theory are also discussed. The main difficulties of the theory are the nonconservation of the number of particles, the treatment of excited states and the up pairing force.