We study the single-photon and two-photon induced emission properties of dye solution embedded with nanoparticle fractal aggregates. The spectral and temporal experimental results show that the lasing threshold of singlephoton absorption of dye solution embedded with TiO2 nanoparticle fractal aggregates is significantly reduced compared with that of a neat dye solution; while that of two-photon absorption does not. These experimental results imply that this low threshold single-photon absorption lasing mainly results from the mechanism of random walking, instead of Anderson localization, unless something about two-photon induced emission is unknown.