In Tokamak, the Alfven eigenmode destabilized by energetic particles can reduce the confinement of energetic particles, which is against the self-sustained burning, while the Alfven instabilities depend strongly on the energetic particles distribution function, so it is crucial to acquire a more realistic energetic particles distribution function for studying the effects of the Alfven eigenmode on the energetic particles transport and loss. However, in most of the numerical codes the energetic particle distribution function is always given by an analytical model, for instance, the slowing down...