Abstract: The ultrasonic technique for bonding quality testing of pipeline joint coatings has a broad application prospect. In this paper, the theoretical model of pipeline joint coatings was analyzed for ultrasonic testing. Several pipeline samples of different bonding quality were tested in immersed method, using a specific transducer whose center frequency was 5 MHz. The echo signals of the testing experiment were distinguished into a signal coming from the surface and two signals from the upper and the lower interface of the adhesive layer respectively. The changing trends of these signals related to bonding quality were summarized in this paper. Two calculating parameters were introduced in this paper, named as E for total intensity of mixed signal and F for frequency intensity of mixed signal. Both parameters were calculated for signals from different samples and the results were analyzed and compared, which showed that both E and F were available parameters for quality evaluation of pipeline joint coatings, as the calculation results of E and F could represent the bonding quality to some extent.