The scanning area limitation (SAL) and maximum flying velocity (MFV) in laser flying marking system are analyzed. Under the same SAL, the influence of grapics entering into the different direction of scanning area on the maximum marking offset (MMO) is studied. Under the condition of the uniform motion, the relationship between MFV and maximum markable time (MMT) as well as MMO is deduced. For the graphics entering scanning area horizontally and vertically, the experiment of laser flying marking using first entering first marking(FEFM) scanning algorithm is carried out. At different markable time, the experimental MFV value agress well with theoretical ones.