The invention relates to a design method of the free tangent camber height of non-uniform root thickness less-leaf tapered leaf springs and belongs to the technical field of suspension less-leaf tapered leaf springs. According to the design method, the free tangent camber height of the non-uniform root thickness less-leaf parabolic tapered leaf springs can be designed according to the number of the leaf springs, structure parameters of the leaf springs, elasticity modulus, the thicknesses of root pads and end pads, the initial tangent camber height of the first assembled and clamped leaf spring, and the design required value of pre-clamping stress of the leaf springs. Prototype testing shows that the design method of the free tangent camber height of the non-uniform root thickness less-leaf tapered leaf springs is correct and is a reliable technical method for design of the free tangent camber height of the leaf springs. By means of the method, the accurate and reliable design value ofthe free tangent camber height of the leaf springs can be obtained, the design level and reliability of products and vehicle running safety can be improved, and the service life of the products can be prolonged; and meanwhile, the design and testing cost is reduced, and the product development speed is increased.