We investigate the surface thermophysical properties (thermal emissivity, thermal inertia, roughness fraction and geometric albedo) of asteroid (99942) Apophis, using the currently available mid-infrared observations from CanariCain on Gran Telescopio CANARIAS and far-infrared data from PACS on Herschel, based on the Advanced Thennophysical Model. We show that the thermal emissivity of Apophis should be wavelength dependent from 8.70 mu m to 160 mu m, and the maximum emissivity may appear around 20 mu m, similar to that of Vesta. Moreover, we further derive the thermal inertia, roughness fraction, geometric albedo and effective diameter of Apophis within a possible 1 sigma scale of Gamma = 100(-52)(+100) Jm(-2) S-0.5 K-1, integral(r) = 0.78 similar to 1.0, p(v) = 0.286(-0.026)(+0.030) and D-eff = 378(-25)(+19)m, and 3 sigma scale of Gamma = 100(-100)(+240) Jm(-2) s(-0.5) K-1, f(r) = 0.2 similar to 1.0, p(v) = 0.286(-0.029)(+0.039) and D-eff = 378(-29)(+27) m. The derived low thermal inertia but high roughness fraction may imply that Apophis could have regolith on its surface, where stronger space weathering but weaker regolith migration has happened in comparison with asteroid Itokawa. Our results show that small-size asteroids could also have fine regolith on the surface, and further infer that Apophis may have been delivered from the Main Belt by the Yarkovsky effect.