The structure of progressive addition lenses (PALs) was introduced. A method of bi-directional fitting meridians of PALs was proposed. Two polynomial curves were fitted bi-directionally from the far and near points of the PALs to obtain meridians that meet the design requirements. Based on this, the curve cluster which was orthogonal to the meridian and meeting the design requirements was selected as the contour line. The vector height data of each point on the PALs was calculated to obtain the entire surface shape. The design results show that the bi-directional fitting method of designing the PALs′ meridians provides the flexibility to adjust the rate of increase of the focal power on the meridians compared to the single higher-order polynomial curve describing the meridians. The individual needs of the wearers can be met to control the focal power and astigmatism of the PALs in the far and near vision zones as well as in the gradient channel. When the same lenses parameters and different bi-directional fitting meridians are chosen, corresponding demanded visual area can be obtained for PALs. The designed PALs were processed, and the finished PALs were measured. It is shown that the performances of the PALs obtained by processing are consistent with the performances of the designed PALs.