According to the characteristic of prepreg tow applied in grid automatic fiber placement, the prepreg by domestic T800/603B is slit into tows which is suitable for mesh laying width according to grid size. Taking slitting width of 5mm and 10mm prepreg tow for example, the preparation technology of which was researched. In addition the accuracy of slitting width, the strength of overlap joint and damage situation of slitting prepreg tow edge were studied. Results showed that different widths of the tows cut out can meet the requirements of prepreg tow applied in grid automated fiber placement.