In order to breed new corn varieties suitable for planting in the mountainous areas of Southwest China to satisfy the seed requirements of local farmers, a white-grain corn single cross variety ‘Baoyu No.19’ was bred by using the self-bred inbred line ‘Bao123’ as the female parent and ‘Bao 129’ as the male parent (‘Bao 123’בBao 129’). In the corn variety joint trial at mid-to-high altitude regions of Yunnan Province for two consecutive years (2021-2022), its average yield of two-year regional trials was 11202 kg/hm², which was 11.9 % higher than that of the control; the average yield of the production trial was 10663.5 kg/hm² in 2022, the yield increase was 8.9 %, and the yield increase point rate was 100%. This variety belonged to the mid-maturing large-ear type variety with growth period of 122 daysand good quality. The average ear length was 19.8 cm, ear diameter was 5.2 cm, number of grains per ear was 582 1000-grain weight was 355 g, seed rate was 86.3%, and grain bulk density was 784 g/L. The variety is resistant to northern leaf blight and sheath blight, moderately resistant to gray spot and southern rust, and has strong lodging resistance. It is suitable for planting at an altitude of 1000-2000 m in Yunnan Province. It was approved by Yunnan Province Crop Variety Approval Committee in 2023, with the advantages of high yield, large ear, density tolerance and wide adaptability, and its comprehensive performance was outstanding. The breeding process, characteristics, yield performance, cultivation practices of ‘Baoyu No.19’ were introduced to provide a theoretical basis and technical support for its demonstration and promotion, aiming to expedite the large-scale production and application of ‘Baoyu No.19’.