A new method of on-line 3D measurement based on phase measuring profilometry(PMP) has been proposed. It only needs to ensure the phase-shift direction of the projected sinusoidal stripe perpendicular to the object′s moving direction. Though the spatial coordinates of the captured distorted stripe images by CCD are inconsistent, by pixel matching algorithm, this inconsistency can be excluded, in addition, the equivalent phase-shifting distorted patterns needed by PMP can been obtained successfully. The profile of the measured object can be reconstructed which put the on-line 3D measurement into practice. A contrast experiment on a known plane inspected by the on-line PMP and the traditional static PMP is carried on, and the difference of mean square deviation between the two methods is only 0.007 mm,which shows the high veracity of the on-line PMP.A complex workpiece has also been on-line inspected, and the 3D profile of the workpiece can be reconstructed perfectly, which shows the feasibility and validity of the on-line PMP.