Abstract: The ultrasound image fusion method based on the Local Fundamental and Harmonic spectral peak Ratio(LFHR) is proposed.First,the fundamental and harmonic components of the ultrasonic Radio Frequency(RF) signals are separated.The weights of both components are determined according to their spectral peak ratio.Then,the fused RF signals are produced with weighted average of the fundamental and harmonic components.Finally,the ultrasound fused images are generated by the framework of demodulation,logarithmic compression and interpolation/downsampling.Experimental results based on simulations of inhomogeneous cysts show that the contrast,contrast-to-noise ratio,and tissue-to-clutter ratio of the fused images based the proposed method are 2.44,2.80 and 3.22 times more than the original images,respectively.The harmonic energy is increased by 83%.The clinical experiments with the human carotid artery also validate the effectiveness of the proposed method.In summary,the fusion B-mode images produced by the LFHR method possess rich details,clear tissue contour,and improved quality.