The invention relates to a signal processing system based on target detection, and the system comprises EDO DRAM storage equipment which is used for storing imaging features of a warm light fluorescent lamp, imaging features of a daylight fluorescent lamp and imaging features of a cold light fluorescent lamp in advance; channel value analysis device used for obtaining a fluorescent lamp area in aninstant processing image, respectively carrying out numerical matching on the overall red channel value of the fluorescent lamp region and the overall red channel values of the warm light fluorescentlamp pattern, the daylight fluorescent lamp pattern and the cold light fluorescent lamp pattern so as to take the fluorescent lamp type of the pattern corresponding to the closest overall red channelvalue as a reference fluorescent lamp type to be output. The signal processing system based on target detection is reliable in operation and effective in configuration. The fluorescent lamp type of the environment where the mobile phone camera is located is analyzed by adopting a targeted analysis mechanism, and the corresponding white balance compensation value is set based on the analysis result, so that the shooting effect of the mobile phone camera is ensured.