The resolution of spectroscopy SPR (surface plasmon resonance) analytical instruments is mostly depended on the sensitivity of sensors and the wavelength resolution

which is relate to the instrument noise levels. But

as we know

the wavelength range of high-resolution spectroscopy is usually very narrow. In order to obtain higher resolving and widen the dynamic range

we analyses the noise sources and their type. These noises can be divided into two types based on the relation to the light source intensity. One is the noise in the intensity of light emitted by the light source and the shot noise

the other is the noise caused by temperature and supporting circuitry. SPR curve

which are involved in data analysis

has been optimized with the signal to noise ratio of spectroscopy SPR analytical instruments. The optimization result is that the optimization SPR cure should be between the Reflectance R1 corresponding to strongest SPR signal and the Reflectance R2 corresponding to strongest signal to noise ratio. And we put forward a part centroid method for data analysis. The experimental results indicate that the analytical instruments resolution has been improved by nearly ten times; the dynamical range of measurement has been enlarged two times. The Glycerin solutions

which are the Refractive index between 1.3325 and 1.3600

are tested. The correlation coefficients are larger than 0.99

that mean this method has not caused unfavorable influence on the result linearity.