The study for surfaced-immobilized nucleic acid probes in nanometer region in response to hybridization and to discrimination ofdifferent target nuclei acids. The hairpin locked nucleic acid (LNA-HP) isselected to be the probe molecule, and target molecules include perfect complementary (PC) and single mismatch (1MM). The self-assembledLNA-HP molecular nanospot is successfully prepared by liquid phaseAFM (Atomic Force Microscope)-based nanolithography technique, then in situ hybridization is carried out by using different targets (PC/1MM).To obtain the information of structure change, we use AFM to analyze therelative heights in the process of hybridization. The experimental results point out that (1) the structure changes of surface probe molecules maycorrelate with the AFM signal when target sequence hybridizes to the probe, (2) miniaturization of the size of the nucleic acid probe may promote hybridization efficiency and enhance the discrimination between PC and 1MM. Studies on whether the different chemical impetus in solution can affect conformation of the human telomeric DNA of sequence is conducted. A human talomeric DNA composed of ( 5¡¦-TTAGGG-3¡¦:5¡¦-CCCTAA-3¡¦ ) repeats, with a 100-200 nt ( T2AG3 ) repetitive unit overhang at 3¡¦ ends is chosen. This extended single-stranded sequence is called G-rich DNA, which forms the special G-quadruplex structure in solution containing sodium ions or potassium ions. The single-stranded sequence composed of ( C3TA2 ) repetitive units called C-rich DNA displays the i-motif folded structure in the low pH environment. These biomimetic DNA¡¦s are thiol-modified to self-assemble on gold surfaces. Separate measurements with AFM (the molecular thickness and rootmean- square roughness of the self-assembly monolayer of DNA ) and CD( circular dichroism ) ( structure characterization ) confirm the conformational changes of G-rich and C-rich DNA¡¦s on gold surface are indeed dependent of the presence of cations and protons.