With view to the sealing failure of premium connection tubing still exists after the downhole,the combined detection technology of metal magnetic memory(MMM) and ultrasound was proposed to detect the sealing performance of the joints.A MMM detection system was built to collect the magnetic memory signal of the joints before and after makeup,and the characteristic parameter magnetic memory signal gradient value was extracted and analyzed.The results show that the magnetic signal gradient value can characterize the thread shape,and the stress distribution of the engaging thread is uneven after makeup,and the magnetic signal gradient value is large at the beginning of the thread,so the stress concentration is high.The ultrasonic testing system was set up to collect the echo signal of the sealing surface before and after makeup,the acoustic intensity reflection coefficient was calculated,and the contact stress distribution of the sealing surface was obtained based on the relationship between the reflection coefficient of sound intensity and the contact stress.The results show that the high contact stress is maintained on the annular belt of the sealing surface after makeup,which has certain sealing ability.The magneticacoustic detection method realizes the detection of the stress concentration of the threaded and the contact stress distribution on the sealing surface,and then the sealing performance can be evaluated.It provide a safer and more effective detection method to ensure the service of tubing down the well.