Abstract: A spring formed with an abnormal-shape cross section (a non-circular cross section) specially used as a vehicle shock absorber is a string whose cross section is shaped rectangular, trapezoidal, single-edge arced or oval. Compared with a spring formed with a circular-shape cross section, the spring formed with one of foresaid abnormal-shape cross sections has some or all of the following functions: The stroke can be increased under the condition of a same free height; it can be prevented from broken after its load area is enlarged; it can reduce weight under the condition of a same stroke; it can enhance resistance to huge outer stress and thus prolong its service life and it can be received and positioned in a very small space.