a packaging bag line - folding and sealing machine includes a first sealing unit and a second sealing unit for sealing a packaging bag therebetween , a first rocker arm and a second rocker arm mounted at the first sealing unit , a locating block , a first link coupled between the first rocker arm and the locating block , two line - folding units , and two second links coupled between the second rocker arm and the line - folding units for moving the line - folding units to make folding lines on the packaging bag between the first and second sealing units upon movement of the first sealing unit relative to the locating block . the application of the packaging bag line - folding and sealing machine greatly improves the packaging quality of packaging bags , and allows adjustment of the line - folding units to fit different sizes of packaging bags , enhancing user convenience .