To enhance multi-source images fusion accuracy,an adaptive fusion method based on image quality assessment parameters in finite discrete shearlet transform (FDST) domain is proposed.Source images a re decomposed to subband images with multi-scale and multi-direction by FDST.The low-frequency subband fusion rule is based on structural similarity index with spatial frequency as co efficient weights and the fusion rule of regional window spatial frequency selection max is adopted in the high frequency subbands.Fused low and high frequency coefficients are reconstructed to image by finite discrete shearlet in verse transform.Corresponding fusion experiments are done by several sets of different modality images and objective performance assessments are conducted for fusion results.The experi mental results indicate that the proposed algorithm performs better in subjective and objective assessments than a few existing multi-scale fusion tec hniques in the literature and can obtain better fusion performance.