The design of the warp and weft density of the fabric should also be combined with the use of the fabric. For example, the characteristics of tough silk fabrics are light and transparent. In order to maintain this feature, we should not only select the warp and weft silk thread with relatively fine linear density, but also reduce the warp and weft density. In order to keep the fabric elastic, not weak, not splitting, the density of warp and weft should be balanced as much as possible, and the warp and weft should be given more twist. For another example, when designing trumpet silk, in order not to affect the sound quality and maintain excellent permeability, the density of warp and weft should also be completely reduced. Another example is the decorative silk used for pasting, such as the silk used for mounting Chinese paintings, the fabric used for book binding, the wall silk, and the brocade used for gift boxes, which can greatly reduce the warp and weft density on the premise of ensuring the decorative effect. On the contrary, the density of silk taffeta used for making high-grade dresses is usually higher than that of plain fabrics in order to make the fabric hard and crisp, and fully reflect the unique "silk ring" characteristics of real silk.

The theoretical density can be calculated based on the interlacing of yarn diameter and weave structure (wool fabrics have been introduced), but this calculation of density is not completely useful, because the production conditions of each production unit are different, as well as the above five factors that affect the density design, resulting in a positive difference in the actual density.

In the actual production process, the weft density of the fabric is smaller than the warp density, mainly because: the raw materials adopted by the warp are better, the machine tension is large, the silk thread is flat, and the silk is complete, which has a great impact on the texture of the fabric. And the warp yarn is generally thinner than the weft yarn, which is conducive to improving production efficiency. At the same speed, the weft density is small and the output is high. In addition, the weft density is convenient for production, and it is convenient to remove the weft when weaving defects occur.
The ratio of warp density to weft density should be determined according to the linear density of warp and weft yarn, weave structure and fabric use characteristics. For example, the ratio of warp and weft density of georgette is very close, generally not less than 10%, and the density of satin fabric is very high. The difference in the ratio of longitude and latitude density is 50-60%.

From the design of new varieties, if there is no special requirement, the weft density of plain fabric should be 20% - 30% less than the warp density, the twill should be 30% - 40%, and the satin should be about 50%.

If the weft density of single-layer fabric is greater than the warp density, it is unreasonable and should be spared. However, heavy weft fabrics, especially jacquard fabrics composed of multi-color weft, may have more weft density than warp density, which is the need of structure and can be treated as an exceptional case.