The dynamic process of the small-scale self-focusing of ultrashort laser pulse is experimentally investigated. By using tabletop femtosecond laser, the pulse which is spatially modulated by the crossed-fiber diffraction passes through the carbon bisulfide. With different input power, the small-scale self-focusing of the pulse was obtained. By analyzing the contrast of the beam, we find that the small-scale self-focusing does not increase all along with the increasing of input power, but some new growth points appear in different places. They compete with each other, and finally lead to multiple splitting. The experimental results confirmed the numerical simulation.