Chemical enhancement can improve the heavy metal phytoextraction efficiency of hyperaccumulator from soil. A pot experiment was conducted to study the effects of different dosage and combinations of biodegradable chelating agents L-glutamic acid N, N-diacetic acid (GLDA) and liquid fertilizer on the absorption of Cd and Zn by hyperaccumulator Sedum alfredi, and evaluate the environmental risk of their leachate. The results showed that the single use of GLDA or liquid fertilizer both increased the extraction efficiency of Cd and Zn of Sedum alfredii. The phytoextraction of Cd and Zn in the treatment with 1.25 mmol/kg GLDA was 1.36 and 1.46 times as much as that of the control, respectively, and the treatment with 0.5 g/kg liquid fertilizer also increased phytoextraction of Cd and Zn by 1.40 and 1.43 times, respectively. The treatment with low dose of GLDA or liquid fertilizer resulted in highest Cd phytoextraction efficiency, which reached 41% to 42%. The concentration of heavy metal in the corresponding leachates of these two treatments were also lower than that of the control, indicating lower environmental risk. When the high dose of liquid fertilizer (2 g/kg) was combined with GLDA, the phytoextraction of Cd and Zn by S. alfredii was lower than that of the control. These results indicated that GLDA and liquid fertilizer had potential to enhance phytoremediation of S. alfredii, and it was better to use these two reagents separately and in low dosage. These preliminary conclusion needs further verification with field experiments.