An arc in the plane that is tangent with the base cone of the spiral bevel gear

and absolutely rolling on the cone surface will form the surface of a spiral bevel bear with spherical involutes tooth form

a new precisely cutting way of the spiral bevel gear based on the principle above is discussed in detail. If the arc is made as the edge of the cutting-tool

then it will cut the surface of a spiral bevel gear

i.e. the precise spherical involutes tooth form

and with no theoretic error. This "gear surface’s producing line cutting method" is defined here. And the actualization way of the spiral bevel gear face cutting and the feasibility of its application are studied through the theory and the tests with the gear surface’s producing line cutting method. The principle of the new cutting method is discussed; the machining tool and the cutter are designed; the principium cutting test is carried out. The theory and the tests prove the correctness of the gear surface’s producing line cutting method. There are no theoretical errors of the tooth form

the gears could be exchanged each other

surface touch areas are adjusted easily

and this cutting method also have the characteristics like high efficiency

simple structure of the machining tool

and low cost etc. From the characteristics above

the methods are best

and have very good feasibility. The principle and the method initiate a new way to cutting spiral bevel bear.