We report on the tuneabilities of Anderson localized light in random scattering systems and its lasing characteristics. By use of FDTD method, we investigated the impulse response of two-dimensional scattering systems consisting of closely packed dielectric particles, and analyzed the localized modes. We revealed the frequencies of the localized modes to be capable of being tuned by changing the structural parameters of the system: diameter, filling factor, and refractive index of the particles. It was also found to be able to tune the Q (quality) factors of the localized modes by changing the system size of the entire medium. Furthermore, by combining Maxwell's equations with rate equations for electron's system, we also theoretically demonstrate how the localized area serves as a laser "resonator" and random lasing is induced.