The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To control the respiratory motion effectively during the radiotherapy of lung cancer without any side effects, a novel control method was introduced in the lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments were conducted for each volunteer, under the guidance of a professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration was recorded under the normal state and hypnosis, respectively. The mean value and the root mean-square (RMS) of the breathing amplitude were 16.2 mm and 8.6 mm during the hypnosis state, while they were 37.4 mm and 23.9 mm during the normal state. It can be seen that the mean value and the RMS during the hypnosis state were 56.6% and 64.2%, smaller than those during normal state, respectively. Moreover, the stability of the peaks and the similarity of the adjacent wave were also analyzed. The passing ratio of γ index between different cycles during the hypnosis state was 16.4%, higher than that during the normal state. Results demonstrate that the hypnosis intervention can be an alternative way for the respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of the respiratory cycle. The proposed method will find applications in the image guided radiotherapy.