To solve the problem that the covering device of sugarcane cannot be adequate for the agronomic standards of seed cane setts planting, a soil-covering and film-mulching device for sugarcane transverse planting was designed. The device includes a soil-covering part, soil-compacting part, and film-mulching part. Through theoretical analysis of key components, the factors affecting the cane seed covering quality for the device were obtained. A quadratic orthogonal rotation regression test was conducted by a homemade prototype to explore the effects of disk diameter, central distance, disk depth in soil, and dip angle on soil covering thickness. The results showed that the above factors all have an extremely significant effect on the soil covering thickness, and the effect degree of each factor from high to low is central distance, disk depth in soil, dip angle, and disk diameter within the range of test parameters. The optimal parameter combination, with the disk diameter, the dip angle, the central distance, the disk depth in soil, and the diameter of the soil-compacting wheel being 304.7 mm, 55.1°, 386.5 mm, 32.4 mm, and 300 mm, respectively, was obtained by Design-Expert software and verified by comprehensive field tests. The results showed that the covering thickness is in the range of 94–111 mm, the average value is 102.6 mm, and the breakage rate is no more than 2.6%. The emergence rate is 86.4%, which is an improvement of 9.3% over that of a traditional covering device. The results suggested that the device can conform to the agricultural covering standard of sugarcane planting and provide a design basis for the application and popularization of the soil-covering and film-mulching device.