摘要： A label-free and high sensitive shear horizontal surface acoustic wave (SH-SAW) biosensor for the nucleic acid detection of Pseudomonas Aeruginosa was developed in this work. An effective detection cell was fabricated by dint of acrylic material. The base frequency of the SH-SAW biosensor fabricated on 36°Y-X rotated black LiTaO3 piezoelectric substrate was 210 MHz. The self-assembled monolayer was formed on the gold surface of the sensitive area, and the increase of mass loading in the sensitive area leads to phase shift of SH-SAW. In this work, the detection limit has been improved by 3–4 times than that in our previous works, which is 1 nmol/L for the nucleic acid of the Pseudomonas Aeruginosa. And the phase shifts related to detection sensitivity are also elevated to 4 ° after the specific binding of the ss-DNA probes and the complementary sequences. In this study, the plot of phase shift against the logarithm of concentration of Pseudomonas aeruginosa nucleic acid was found to be linear over the range from 0.1 nmol/L to 1000 nmol/L with a correlation coefficient 0.98777. The detection limit as low as 0.28 nmol/L was achieved for Pseudomonas aeruginosa nucleic acid in this paper.