Abstract: The strength of concrete attacked by sulfate was tested by ultrasonic technique. The test results show that ultrasonic velocity of the concrete varies in different deteriorated concrete in sulfate environment, and the velocity has a favorable regression relationship with the strength of attacked concrete. By recursively analyzing the test data, the functional equation between strength of attacked concrete and velocity of ultrasound was obtained, and the certain reference for testing the strength of attacked concrete by using ultrasonic test method is presented.