A method for hydrogen volume fraction test in hydrogen rich water by composite electrodes is proposed. The test shows that for the three-electrode system with two platinum wires as working electrode and auxiliary electrode and Ag/Ag Cl as the reference electrode

with constant external potential. The potential of the working electrode will not change with the potential of the auxiliary electrode

and the sensitive electrode curve can be realized. The sensor has good sensing performance for the hydrogen rich water of volume fraction of（ 0. 1～ 0. 8） × 10

-6

. The electrochemical sensor current has a positive linear relationship with the hydrogen volume fraction

and its response time is less than 5s.