‘Guoxia No.1’ is a new pakchoi F1 hybrid developed by crossing 2 self-incompatible lines ‘Y436’and‘ Y231-k’．This variety is of dwarf plant type with beautiful appearance．Its leaves are stretched and green in color with broad petiole and less wax powder．It is sowed in August 10 in Bejing area．Forty days after sowing，its plant is 19 cm in height and 35 cm in width．Its petiole is 4.9 cm in width and 1.1 cm in thickness．The average single plant weight is 231 g．It can yield 45.15 t·hm-2．It is resistant to TuMV and highly resistant to black rot and downy mildew．It is tolerant to heat and moisture．It is suitable for summer and autumn cultivation．It has been extended to Beijing，Tianjin，Shanghai Municipalities，and Hebei，Fujian and Shandong Provinces with over 30 000 hm2 total areas．