The invention discloses a disinfection sterilization medical ultrasonic coupling medium with the bactericidal function and used in the ultrasonic detection and treatment of skin and cavitary mucosa and a preparation method of the coupling medium, wherein, the ultrasonic coupling medium comprises propylene glycol, de-ionized water and one viscosity modifier of the hydroxy ethyl cellulose, carbomerand hydroxy propyl cellulose. The coupling medium further comprises a fungicide of 0.05 to 0.15 percent and the constituents of the fungicide are any one of polyhexamethylene biguanide, benzalkonium chloride, benzalkonium bromide, chlorhexidine acetate, trichlorobenzene phenoxy diphenyl ether and nanometer silver or any combination of the olyhexamethylene biguanide, the benzalkonium chloride, thebenzalkonium bromide, the chlorhexidine acetate, the trichlorobenzene phenoxy diphenyl etherand, and the nanometer silver; the preparation method used for preparing the ultrasonic coupling medium is as follows: dispersing the hydroxy ethyl cellulose in the propylene glycol, stirring and dispersing the hydroxy ethyl cellulose by adding enough water, heating to 75 to 80 DEG C, preserving the heat for 30 minutes to cool the hydroxy ethyl cellulose and the propylene glycol to 45 DEG C, adding the fungicide to stir and cool the fungicide, the hydroxy ethyl cellulose and the propylene glycol to obtain the filled coupling medium. Tests show that the products of the coupling medium have fast and long sterilization effect and meet the requirements of various related standards.