The invention provides a design method of a spring for a pan open-close cover and a pan. The pan comprises a pan body and a pan cover which is hinged to the pan body, the spring comprises a first spring and a second spring, when the pan cover conducts cover opening motion, the first spring provides bias force which makes the pan cover move toward the cover opening direction for the pan cover, and the second spring provides bias force which makes the pan cover move toward the cover closing direction for the pan cover; the design method comprises the steps that the maximum opening angle in the cover opening state of the pan cover is defined as theta, the torque generated by the first spring is T1, the torque generated by the second spring is T2, the torque generated by gravity of the pan cover is TG, and when the opening angle of the pan cover is within the whole range of 0 degree to theta, the first spring and the second spring always meet a first condition that T1 plus T2 minus TG is larger than 0; accordingly, when the pan is at any position in the cove opening process, it can be guaranteed that the driving force which is applied to the pan is larger than damping force, and according to the design method, it is guaranteed that the pan can successfully open in place.