In this study, an effective wet-chemical route was developed in an aqueous solution for the synthesis of spindle-like palladium nanoparticles(Pd NPs). Spindle-like Pd NPs in high-yield were successfully synthesized by using cetyltrimethylammonium chloride(CTAC) as surfactant and ascorbic acid(AA) as reduction reagent. The influence factors including the concentration of CTAC, AA, and Na I, as well as the reaction temperature for synthesis of spindle-like Pd NPs were systematically investigated. The formation mechanism of spindle-like Pd NPs was proposed on the basis of these experimental results. Spindlelike Pd NPs with high density of twins and sharp edges exhibit enhanced catalytic activities for the reduction of 4-nitrophenol. In this study, an effective wet-chemical route was developed in an aqueous solution for the synthesis of spindle-like palladium nanoparticles (Pd NPs). Spindle-like Pd NPs in high-yield were successfully synthesized by using cetyltrimethylammonium chloride (CTAC) as The influence factors include the concentration of CTAC, AA, and Na I, as well as the reaction temperature for synthesis of spindle-like Pd NPs were systematically investigated. The formation mechanism of spindle- like Pd NPs was proposed on the basis of these experimental results. Spindlelike Pd NPs with high density of twins and sharp edges exhibit enhanced catalytic activities for the reduction of 4-nitrophenol.