In order to tune the longitudinal localized surface plasmon resonance(LSPR) wavelength of monodisperse gold nanorods from near infrared to visible light region,monodisperse bimetallic nanorods， with core shell structure based on silver as shell(Au@AgNRs),were synthesized by in situ reduction reaction,and their silver shell thickness could be modulated by the used amount of AgNO3.The morphology,monodispersity and chemical composition of Au@AgNRs were identified by high resolution transmission electron microscopy and X-ray energy dispersive spectroscopy.With the increase of their silver shell thickness,the LSPR effect of Au@AgNRsis was gradually enhanced,and their longitudinal LSPR peak was blue shifted from near infrared to visible light region.When the silver shell thickness was increased 1 nm,the longitudinal LSPR wavelength was decreased about 12 nm.The prepared Au@AgNRs has a good application prospect in visualization sensor.