This work investigated the transient characteristics of tissue attenuation coefficients before, during and after HIFU treatment at different total acoustic powers in ex vivo porcine muscle tissues. Initially, preliminary data for the changes in attenuation coefficient induced in ex vivo porcine muscle tissues due to coagulation were obtained. The data indicated that changes in least squares attenuation coefficient slope (Δβ) and attenuation coefficient intercept (Δα 0 ) were both potentially reliable indicators of tissue thermal damage. Then, pulse-echo radiofrequency data were acquired to estimate Δβ and Δα 0 , and to construct Δβ, Δα 0 , and B-mode images.Dynamic changes of Δβ and Δα 0 were correlated with conventional B-mode ultrasound images over the HIFU treatment process. During HIFU treatment, Δβ and Δα 0 increased rapidly with the appearance of bubble clouds in the B-mode images, and bubble activities appeared as strong hyperechoic regions in the B-mode images, caused fluctuations in the estimated Δβ and Δα 0 values. After the treatment, Δβ and Δα 0 gradually decreased, accompanied by fadeout of hyperechoic spot in the B-mode images, until they were stable at 10 minutes post-treatment, at 0.84 ± 0.11 [dB/(MHz.cm)] and 1.36 ± 0.19 [dB/cm], respectively. Finally the results showed that Δβ and Δα 0 images had significantly higher contrast to speckle ratios than the conventional B-mode images.