Objective     To compare 2 methods to immobilize probes on the surface of gold membrane and select the better one for aptamer immobilization of aptamer-based piezoelectric quartz crystal sensor.      Methods     Anti-IgE aptamers were immobilized on the gold surface of piezoelectric quartz crystal sensor with thiol method or biotin-avidin method. The changes of frequency were compared in reactions with different concentrations of IgE.      Results     Biotin-avidin method obtained higher frequency changes in the reactions of IgE

lower limit of detection and wider liner range than thiol method. For biotin-avidin method

there was significant linear correlation between frequency changes and the concentration of IgE with the correlation coefficient of 0.994 5.      Conclusion     The thiol method which is proved effective for probe immobilization on gene sensor is unfit for aptamer immobilization. Biotin-avidin method has a better ability to immobilize probe on the surfaces of aptamer-based piezoelectric quartz crystal sensor.