The sun is the most energetic particle accelerator in the solar system, producing ions of up to GeV and electrons of up to several MeV. Large solar flares are the most powerful explosions in the solar system. The accelerated above 20 keV electrons and the greater than 1 MeV ions appear to contain 10%-50% of this energy, indicating that the particle acceleration and energy release processes are intimately linked. Hence, one of the most fascinating aspects of solar flares is how the particles are accelerating to high energies. Particle acceleration by direct current (DC) electric field in a reconnecting current sheet is considered as one of the popular mechanisms of the acceleration of energetic particles during solar flares. Numerical simulations of electrons and protons acceleration through the test approach and studying on the energy spectrum and the trajectories of these energetic particles are very important to understand the process of particle acceleration and flare physics. This thesis is organized as follows: In Chapter 1, We first present a brief introduction to solar flares, including hard X ray (HXR) and radio observations of flares, some basic concepts and models of magnetic reconnection, and the standard model for solar flares, all of which are relevant to this thesis. In Chapter 2，we summarized the basic knowledge to three particle acceleration mechanism, These involve the stochastic acceleration by MHD turbulence generated in fast plasma reconnection outflows; shock-drift acceleration and diffusive-shock acceleration; and super-Dreicer acceleration in a reconnecting current sheet. In Chapter 3，Kinematic characteristics of electrons and protons in the magnetic reconnecting current sheet in the presence of a guide field are investigated. Particle trajectories are calculated for different values of the guide field by a test-particle calculation. The relationship between the final energy and the initial position has also been studied. We found that the addition of a guide field not only allows particles to get more energy and not only results in the separation of electrons and protons, but also causes the reconnecting electric field to selectively accelerate electrons and protons for different initial positions. The energy spectrum eventually obtained is the common power-law spectrum. The spectrum index depend on the guide field, the background magnetic field, and the initial distribution. In Chapter 4，kinematic characteristics of the accelerated particles in the current sheet including multiple X-points and O-points were investigated. The energy spectra for both particle species have a double or multiple power-law shape. Accelerated particles are either trapped within magnetic island regions, or escape the current sheet mainly along the open magnetic field. Also, protons and electrons are ejected from the current sheet in different directions. In the last chapter, we summarize this thesis and give prospects of further studies.
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