Abstract: In this paper, we described adifferential power analysis attack on the Montgomery Ladder algorithm based on the finite field GF(2^m)． We first implemented the algorithm with Verilog HDL, and then synthesized it to the netlist using the Charted 0.35μm CMOS technology, thus we can get the power information accurately． We performed a ZEMD differential power analysis attack on this algorithm subsequently, and use the abscissa of P₂, a variable of the Montgomery Ladder algorithm, as the intermediate variable to classify the power curves, the result shows that the Montgomery Ladder algorithm couldn′t resist the ZEMD differential power analysis attack. So the algorithm is not secure enough, we need to take some more protective measures in practice.