Several focusing field emission devices are simulated by the MAGIC particle-in-cell code program. The emission current, anode current, and focusing effect are compared and analyzed. The results show that the coaxial focusing structure has the smallest electron dispersion width, the coplanar focusing structure has good focusing effect and simplest fabrication process, and the ridge focusing structure has the largest anode current. The overall consideration reveals that the coplanar focusing structure is the better choice for display application.