At present, the detecting method with two transducers is always adopted in detection of concrete structure, but efficiency is quite poor. In the paper a detection method based on linear array transducers is presented to meet the need of rapid detection of internal defects and embedded target inside concrete structures. The scanning signals between interval transducers are used to increase array dimension maximum to amalgamate detecting data. After the structural noise is filtered through effect signal processing method, the concrete structure can be detected effectively by combining with synthetic aperture focusing technique (SAFT) and the structural characteristics of linear array. It can be shown from numerical simulation that this method can not only increase detecting efficiency but also achieve effect ive focus and accurate location to testing object.