A calculation method is put forward about tooth root bending stress of point-line meshing gear.A amendment calculation formula is put forward about tooth root bending stress of big gear.A big gear flexural strength increasing multiple is added in the formula.Through finite element emulation and test
the calculation method is proved about tooth root bending stress of point-line meshing gear.A conclusion is that the flexural strength of pointline meshing gear is higer 15% than involute cylindrical gear at least.