Abstract: To meet the needs of offshore geochemical survey and resources exploration, three reference materials (RM) of the Pearl River Delta sediment are prepared. Being dried and ground into 74 μm, the sample is proved to have good homogeneity by XRF method. The variance test shows the measured F values are less than critical values. Four stability tests on representative elements within two years indicate that the samples have good stability. Twelve laboratories and sixteen reliable analytical methods are involved in the study to finally obtain the certified values of seventy elements. The preparation of standard materials can provide reliable quality assurance for geological survey in estuarine delta areas.