This research is mainly focused on to study microstructure and mechanical properties of AA5051 aluminum alloy deformed by equal-channel angular pressing (ECAP) process at 200˚C and in B_C routes and 4 four passes. The ECAP processing was carried out using die with an intersecting channel angle ‘ϕ’= 120° and corner angle ‘Ψ’= 20°. The results of uniaxial tensile test showed that tensile strength was found to be increased from 115MPa for annealed sample to 239MPa after four passes ECAP in route B_C that shows that the strength in ECAP samples has increased. In addition, the percentage of elongation also decreased in initially passes and then increased slowly. Microstructure and grain refinement of specimens were investigated by optical microscopy and scanning electron microscopy and fractography were investigated by scanning electron microscopy. The grain size of annealed sample was 123μm and decreased to 18μm after four passes ECAP in route B_C. The hardness also increased from 51HV in annealed sample to 90HV the fourth passes.