This paper studies the influence of number particles on microstructure and crystallization of nickel bulk models using the Molecular Dynamics (MD) method with embedded interactive Sutton-Chen potential and periodic boundary conditions. The samples (5324 particles, 6912 particles and 8788 particles) underwent an increase in temperature from 0 K to 2000 K and a decrease in temperature from 2000 K to 300 K with the translate dr = 0.01 giving results consistent with practices. The characteristics of microstructure and crystallization of samples were analyzed through radius distribution function (RDF), coordination number and common neighbor analysis (CNA). Results show that number particles influence the microstructure and crystallization and there is the appearance of structure phase face-centered cubic (fcc), hexagonal close-packed (hcp) and body-centered cubic (bec) in samples at 300 K. Samples with different numbers of particles have different characteristics in microstructure and crystallization.