Ultrasonic testing (UT) for medical examination as well as metal flaw detection is a popular method. From the beginning of ultrasonic testing conducted by Mulhauser in 1931, a lot of new things and technologies emerged in UT testing. This review paper deals with progress in detecting human organs as well as materials flaws and future prospects of UT for metal flaw detection. Study on components of UT system is conducted. Then typical UT inspection system is determined. After that advantages and disadvantages of UT have been reviewed. Major types of waves in ultrasound with considering UT instruments have been reviewed as well. Progress in different areas of UT have been discussed extensively with more emphasis on progress in composite piezoelectric materials, variations of probes, EMAT (Electromagnetic Acoustic Transducer), focused probe, focusing axicon probe, focused phased arrays, LASER (Light Amplification by Stimulated Emission of Radiation) generation of ultrasound, acoustic Holography, and ultrasonic microscopy. At the end future prospects of UT have been reviewed as well as recommendations have been provided.