KDP　crystals　with　different　concentration　of　EDTA　and　KCl　doping　were　fabracated　by　traditional　temperature　reducing　method　from　solutions.　The　light　scatter　of　KDP　crystals　was　observed,　the　transmittance　of　samples　of　the　prismatic　section　and　the　content　of　impurities　(Fe3+,　Cr3+,　Cl-)　in　KDP　crystals　were　measured.　The　results　indicated　that　EDTA　and　KCl　with　low　concentration　(0.01　mol%　EDTA,　KCl<1.5　mol%)　in　solution　can　improve　the　transmittance　of　crystals,　while　high　concentration　(0.01　mol%　EDTA,　2.0　mol%　KCl)　may　aggravate　the　light　scatter　and　reduce　the　transmittance　of　crystals.　The　KCl　doping　with　the　concentration　of　2.5　mol%　could　restrain　the　crystal　growth　and　induce　the　crystal　defects.　The　total　content　of　trivalent　metal　ions　(Fe3+,　Cr3+)　decreased　with　increase　of　doping　concentration,　while　chlorine　element　was　not　found　in　the　KDP　crystals.