Abstract: Detection for a faint astronomical object in daytime is an extremely complex issue because of low targetbackgroundcontrast and low signaltonoise ratio. Some ways to improve the detection probability is studied in this paper. The results show, spectral filtering technology is an effective way to improve signaltonoise ratio. The reasonable choice of field of view is helpful to get higher signaltonoise ratio and contrast. With the reasonable choice of field of view and the effective application of morphologybased detection algorithm, the detection efficiency could be greatly improved.