Improving conductivity of electron and ion was considered to be the significant tendency on pseudocapacitive materials. In this work, a flower-like P-NiAl LDHs electrode materials have been successfully fabricated by hydrothermal synthesis and subsequent phosphatized treatment. Owing to the presence of phosphide, the resulting P-NiAl LDHs electrode showed a high specific capacitance of 2159F g-1 at 1 A g-1 and a good capacitance retention of 85.6% at 20 A g-1, which more excellent than NiAl LDHs electrode. Besides, the P-NiAl LDHs//AC asymmetric supercapacitor exhibited a high energy density of 79.3 Wh kg-1 under a power density of 1033.6 W kg-1 and an acceptable stability of 73.6% specific capacitance retention after 2400 charge-discharge cycles. Consequently, the P-NiAl LDHs nanoflower is one of the better candidates for assembling supercapacitor, and this phosphatized method is a kind of facile and desirable strategies to improve the electrochemical characteristics of LDH-based supercapacitor materials.