In this work,Au NRs were synthesized by a two-step seed mediated growth method,and Au@Ag NRs were synthesized as SERS substrate through the chemical reduction method.The substrate was used to detect R6G as low as 10-18 mol/L.The Au@Ag NRs substrate has a good enhanced effect with enhanced factor of ca.1011.For the glucose deposited on the substrate with concentrations from 10-14 mol/L to 10-8 mol/L,the SERS signal intensity performs a linear change with logarithm concentrations of glucose.The experimental results showed that this method has a potential application prospect in ultra-trace glucose detection and semi-quantitative analysis.