Abstract: To have a competitive leading position in the future, storage ring of Iranian Light Source Facility (ILSF) is designed to emphasize on electron beam of small emittance, great photon flux density, brightness, stability and reliability. I present a possible low field lattice with low natural emittance of 0.96 nm.rad. The linear and nonlinear dynamic properties of lattice and the related Accelerator Physics issues have been covered.