Abstract: Elaborated in the essay is the quality evaluation process flow for the ERW tube which consists on-line NDT，analysis of weld internal structure，destructive tests （flaring and flattening）and hydraulic test. The reasonability of the flow is verified via actual operation cases. And the test results show that the said quality evaluation process flow is in full compliance with the requirements under applicable welded tube specification，being capable of providing basis for massive production and quality assurance of ERW tubes.