As an effective nondestructive diagnosis method without giving any damage to the mud wall on the traditional building, the ultrasonic measurement method was introduced in order to estimate their mechanical properties and shear performance and to make a diagnosis of their damage condition. Comprehensive evaluation for the relationship between the change of ultrasonic transit time and the mechanical property by compressive and shear test was performed. Consequently, it was concluded that ultrasonic transit time showed a very high relationship with the plastic behavior of the mud. On the small mud wall unit with the bamboo lath, it could obviously make grasp in its total estimation of the damage level and pattern with contour mapping by change-ratio of the ultrasonic transit time on each sector of mud wall. Ultrasonic measurement method was proved its high potential on the executive nondestructive diagnosis of traditional mud wall.