Laser Raman spectroscopy is widely applied in marine chemical environmental detection and analysis of substances, as an in－situ, real-time, multisubstance detection sensor technology. Charge-coupled devices (CCD) as the detector of Raman spectrometer are easily interfered by cosmic ray so that some spikes that have random location, intensity and peak width occur on Raman spectra. The presence of such spikes can damage spectral presentation, complicate interpretation, and impede further analyses. The method combined nearest neighbor comparison method (NNC) with median filter was used to detect and remove spike from the measured spectral data of seawater in laboratory. The Raman spectra were divided into two areas firstly: Raman peaks area and the area that has no Raman peaks. The NNC processed the area that has Raman peaks and the median filter processed the area that has no Raman peaks. The result shows that the combined method can remove spike of the full spectra completely on the premise that the intensity of Raman peaks remain unchanged. The method contributes to improving the accuracy and stability of qualitative and quantitative analysis for Raman spectra.