The invention discloses a non-circular gear transmission press and a method for obtaining the shape of a non-circular gear nodal line. The non-circular gear transmission press comprises a power device, a crank, a connecting rod, a sliding block, a driving non-circular gear and a driven non-circular gear, wherein the driving non-circular gear and the driven non-circular gear are meshed with each other; the connecting rod is connected with the crank and the sliding block; the power device is in transmission connection with the driving non-circular gear; and the driven non-circular gear is in transmission connection with the crank. Motion characteristics of the non-circular gears can be obtained by subtracting the motion characteristic of a crank sliding block mechanism in the press from the motion characteristic of the press, and nodal line curvilinear equations of the non-circular gears can be solved by the motion characteristics of the non-circular gears. The invention has the advantages that: motion characteristic curves are changeful; manufacturing precision is high; working efficiency is high; and the motion characteristic curves of the press are simple in obtaining.