Exploring the distribution of focused ultrasound field attracts more and more investigators’ attention. Making use of the heat property of focused ultrasound, we can measure the distribution of temperature to calculate the distribution of focused ultrasound field. During the exploration, we found that the temperature rise rate had a liner relation to sound intensity. So we conducted experiments and got the infrared images with noise. In order to obtain an accurate distribution of focused ultrasound field, it’s necessary to find out a solution to get rid of the noise in infrared images. In traditional, we use hydrophone to explore the distribution of focused ultrasound field even in nonlinear area. So the result got by hydrophone was considered as standard. So the investigation was focused on the experimental validation of a filter which was the most suitable way for image process of infrared chart. So the ability of the filter should be that removing most noise and the distribution of temperature rise rate is unchanged. Six kinds of filters were used to deal with the raw data to obtain related information, from the results, we drew a conclusion that gauss filter was superior to the others filter, and a non- distortion distribution of focused ultrasound field would be get by the use of Gaussian filter.