Abstract: Onion bulblets were used as sowing materials, and three kinds of bulblet sizes were designed by field experiment（5-6 mm, 4 mm and 3 mm）.Two kinds of sowing directions were designed, bulblet root downward and bulblet horizontal placement.The effects of different bulblet transverse diameters and different sowing directions of bulblet root on onion bulb traits, quality and yield were studied, in order to obtain the most suitable bulblet diameter standard.The results showed that the comprehensive evaluation of T1 treatment was the highest, with germination rate of 95.06%,plant height of 57.90 cm, pseudostem diameter of 11.47 mm, leaf number of 7.93,SPAD value of 52.07,fruit shape index of 0.91,single fruit weight of 311.33 g, 2.68 m~2 plot yield of 18.96 kg, dry matter content of 6.33%,soluble solids content of 15.00%,soluble sugar content of 1.63%,pyruvic acid content of 8.71 mg·（100g）^-1FW,vitamin C content of 11.99 mg·（100g）^-1FW.The indexes of the six treatments were analyzed by principal component analysis and evaluated comprehensively.The comprehensive evaluation value was from high to low T1＞T2＞T3＞T4＞T5＞T6.From the comprehensive evaluation, it can be seen that the comprehensive performance of the 5-6 mm bulblet root downward（T1） treatment was good, ranking first, and the growth, quality and yield of onion were optimal.