The large-conductance calcium-activated potassium (BK) channels distributed in both excitable and non-excitable cells are key participants in a variety of physiological functions. By employing numerous high-affinity natural toxins originated from scorpion venoms the pharmacological and structural characteristics of these channels tend to be approached. A 37-residue short-chain peptide, named as martentoxin, arising from the venom of the East-Asian scorpion (Buthus martensi Karsch) has been investigated with a comparatively higher preference for BK channels over other voltage-gated potassium (Kv) channels. Up to now, since the specific drug tool probing for clarifying structure-function of BK channel subtypes and related pathology remain scarce, it is of importance to illuminate the underlying mechanism of molecular interaction between martentoxin and BK channels. As for it, the current review will address the recent progress on the studies of pharmacological characterizations and molecular determinants of martentoxin targeting on BK channels.