Abstract: Two-dimensional density distributions of dense plasmas in laser confinement fusion are revealed with proton imaging. Simultaneous iterative reconstruction algorithm (SIRT) is used to study influence factors of two-dimensional plasma density reconstruction. Effects of plasma density gradient, magnitude of density and initial proton energies on reconstruction errors are investigated. Importance of figuring out rough area and range of simulated plasma zone before simulation is analyzed. Furthermore, an analytical expression between reconstruction errors and noises is established through data analyses.