Abstract: Aluminum alloy is used to make the high-speed train body.Because the bearing pressure of the body is large,the residual stress distribution is urgently needs to measurement.Based on the acoustoelasticity,the residual stress can be measured by ultrasonic method.Ultrasonic stress measurement experimental installation is established with critically refracted longitudinal wave.The residual stress of high-speed train body structure is measured by the system.The safety evaluation virtual model of welded structure concept is proposed.