Abstract: Objective:To study the clinical value of using high frequence planar ultrasound and CDFI to diagnose carcinoma of larynx. Methods:We directly scan 10 cases of laryngeal tumour through cervix in order to observe the tumour's size ,sharp,limit and its inner echo. To observe the color bloodstream in the centure and side of the tumour by using CDFI. According to abundance of the tumour's blood supply.We can use the method of semi-quantitative analysis to grade it .Results: By high frequence planar ultrasound ,we can find 9 cases out of 10 cases of the laryngeal cancer, it display 90%(9/10).Most of the tumour's echo is asymmetric and low(8/9,89%).Display rate of the tumour's,blood flow signal is 100%(9/9),The abundance of the tumour's blood supply are mainly of grade Ⅱand grade Ⅲ. Conclusions: Examming through cervix, high frequence planar ultrasound can clearly display the normal structure of larynx,The discovery rate of the tumour is high .With CDFI to observe the tumour's blood flow signal ,it is of great value in diagnosis laryngeal cancer.