The characteristics of fast electrons (e-) and heavy particles (N2+, N+, N2f, Nf) in the cathode dark space (CDS) of nitrogen dc glow discharge are simultaneously studied by Monte Carlo simulation. The calculated energy and angular distributions of these particles at different positions from the cathode provide a clear picture of their transport behaviours within the CDS. The density and mean energy of these particles indicate that the electrons and the atomic ions (N+) are the main high-energy species and the molecular ions (N2+) are the major ions in the CDS. It can be seen from the energy distributions of the bombarding particles at the cathode surface that the molecular ions and the fast atoms (Nf) are the main active species participating in the cathode nitride material synthesis process. The influence of the backscattering of the electrons from the negative glow to the CDS is also investigated. All the calculated results provide good information on the spatial characteristics of the particles considered in this paper and also their internal connections in the CDS of nitrogen dc glow discharge.