With the purpose of examining the effects of light quality on flowering, the pigment content, quality and carbon metabolism of pakchoi (Brassica campestris L.ssp.chinensis (L) Makino var. communis Tsen et Lee) seedlings on the budding and floweringagetypes, the present study were carried out to use the cultivar ‘Suzhouqing’ as plant material, which were grown under four different light treatments including blue plus red lightemitting diodes (LEDs, B∶R=2∶7), blue LEDs (B), red LEDs (R) and fluorescent lamps (FL) for 120 days. Some indices such as flower buds, open flowers, pigments and ascorbic acid, soluble protein, sucrose, soluble sugar, and starch concentrations were determined. The results showed that. (1) with the extension of flowering time, the numbers of open flowers were significantly larger in seedlings under R and BR than that under FL. The number of flower buds was significantly larger under R and BR than that under FL at the 100^thd. However, the number of flower buds was significantly larger under B than that under FL at the 110^thd and 120^thd; (2) the photosynthetic pigment content of leaves was gradually decreased with the extension of flowering period. The concentrations of pigments were significantly higher in seedlings under BR than that under FL at 100^thd. However, the concentrations of pigments were significantly higher in seedlings under B than that under FL at 110^thd. The concentrations of pigments were the highest in seedlings under BR at 120^thd; (3) the soluble protein and ascorbic acid content in leaves decreased gradually as the flowering time was prolonged. The concentration of soluble protein was higher in seedlings under B than that under FL during the flowering periond. However, the concentration of ascorbic acid was higher in seedlings under B than that under FL at 100^thd. The concentration of ascorbic acid was higher under B and BR in seedlings than that under FL at 110^thd and 120^thd; (4) as the extended flowering, leaf carbohydrate content also gradually reduced, which soluble sugar, sucrose and starch contents were significantly higher under R than that under the other lights. Obviously, compared with the FL, LEDs is more effective for the vegetative growth and reproductive growth of pakchoi seedlings, B is conducive to the vegetative growth of pakchoi, while R and BR are beneficial to their reproductive growth. The R LEDs and BR LEDs lights can be used as the artificial light source for the pakchoi breeding, and it might promote the factory production process of pakchoi.