A simple and efficient method for the determination of Pb and Cd in domestic water and drinking water was developed by combining low-density solvent based dispersive liquid liquid microextraction (LDS-DLLME) with graphite furnace atomic absorption spectrometry (GFAAS). In the LDS-DLLME, a mixed solution of octanol (extraction solvent) and methanol (dispersive solvent) was rapidly injected into the sample solution by a microsyringe to form a cloudy emulsion. With diethyldithiocarbamate (DDTC) as chelating agent, Pb2+ and Cd2+ were extracted into the highly dispersed octanol microdroplets. The mixture was then centrifuged and the chelates of Pb and Cd moving into the organic phase, which was analyzed by GFAAS subsequently. In addition, the experimental conditions were investigated and optimized, such as the type and volume of extractant and dispersant, pH, DDTC concentration and extraction time. Under the optimal experimental conditions, the detection limits of Pb and Cd were 0.15 and 0.03 μg·L-1, and enrichment factors were 87 and 48, respectively, with good linearity and precision. This method has the advantages of simplicity, rapidity, low cost, and high enrichment. It is successfully applied to the determination of trace Pb and Cd in tap water, drinking water and South Lake water.