Abstract: When the solar activity is frequent, especially when it is accompanied with solar flares or coronal mass ejection (CME) driven shocks, a sudden increase of the flux of the solar energetic particles (from dozens of keV to dozens of MeV) can often be detected. The energetic particles produced by the solar activity are named the solar energetic particles (SEPs). In this paper, two typical events of the high-energy particles generated by solar flares and CME driven shocks are reviewed, with a special focus on the effect of the perpendicular diffusion of the SEPs propagating in the interplanetary space. Numerical simulation results are given for different diffusion parameters.