Comparison　investigations　were　performed　for　the　enrichment　method　of　lead　in　environmental　waters,　including　co-precipitation,　ion　exchange　and　cloud　point　extraction(CPE).　CPE　was　selected　as　the　optimal　enrichment　method　because　of　its　less　consumption　of　water　sample,　higher　enrichment　factor　and　simpler　procedure　than　the　other　enrichment　methods.　Pb　contents　in　the　water　samples　from　Tonghui　River　in　Beijing　were　determined　by　high　resolution　continuum　source　graphite　furnace　atomic　absorption　spectrometry　coupled　with　CPE　enrichment.　The　results　indicate　that　the　limit　of　detection　of　the　method　is　0.08　mu　g　.　L-1,　the　relative　standard　deviation　(RSD)　is　1.3%　to　4.　5%　(n=6),　the　recovery　of　Pb　contents　is　93%　to　108%,　and　the　enrichment　factor　of　CPE　method　is　29.　The　Pb　contents　in　the　13　water　samples　from　Tonghui　River　all　conform　to　the　Environmental　Quality　Standards　for　Surface　Water　(Grade　I).　Moreover,　the　Pb　content　in　the　whole　river　exhibits　a　decreasing　trend　from　Tongzhou　district　to　Chaoyang　district.