In order to evaluate the applicability of ReaxFF in Aluminum, some physical properties about aluminum were calculated by reaction force field (ReaxFF), and compared with embedded atom method (EAM), DFT and the experimental value. The result is that the energy and the elastic constant calculated by ab initio and EAM methods are in accord with the experimental well, and ReaxFF values are reasonable. DFT, EAM, and ReaxFF methods could distinguish the face center cubic (fcc), body center cubic (bcc) and simple cubic (sc) structures well. ReaxFF obtains the fcc-Al cohesive energy, E_v=4.0248 eV, while the experimental is 4.05 eV. ReaxFF calculates the vacancy formation energy, 1.136 eV, while the experimental is 0.68 eV. ReaxFF calculates the elastic coefficients not well; ReaxFF predicts the Cauchy pressure, approximate zero, which it always nonzero. Thereby, the energy released and propagation velocity could be researched by ReaxFF well, but it is not good to describe elastic properties. 