A novel interface for on line coupling capillary electrophoresis with hydride generation electrothermal atomic absorption spectrometry (CE-HG-ETAAS) has been developed. The interface performance was examined in detail. The technique could be used to convert arsenic compounds from CE separation to corresponding volatile hydrides determined by HG-ETAAS. This paper aims to explore the best condition in the speciation analysis of inorganic arsenic by using CE-HG-ETAAS. The application of the developed CE-HG-ETAAS to inorganic arsenic speciation in sediment was investigated. The detection limits of As(III) and As(V) were 135 ng/g and 160 ng/g, respectively. Relative standard deviations of arsenic speciation were better than 2%. The recoveries of As(III) and As(V) in the sample with spiking concentration of 2500 ng/g As(III) and 5000 ng/g As(V) were 97.6% and 96.7%, respectively.