The　factors　influencing　grain　refinement　in　constrained　groove　pressing　(CGP)　of　two-phase　alloys　such　as　alloy　composition,　annealing　temperatures　and　die　sizes　were　analyzed.　The　results　show　that　due　to　lower　Zn　content　in　H62　brass,　the　plasticity　of　the　alloy　is　increased　and　consequently　it　is　good　for　CGP　deformation;　along　with　the　annealing　temperature　increasing,　the　β′　phase　increases　but　is　unfavourable　for　CGP　deformation;　and　the　wider　groove　can　reduce　the　stresses　in　the　severely　loaded　region　of　the　workpiece,　and　thus　allow　more　cycles　of　pressing　to　attain　grain　refinement　and　improve　properties.