The invention discloses a hydrogen passivation technology for improving a light failure problem of a mono-crystalline solar cell. The technology comprises the following steps: regulating the conversion quantity, between the high compound state and the low compound state, of B-O defect in a silicon substrate by using the H in the SiN:H film on the solar cell surface and controlling the current andtemperature and like elements exerted on a cell, and regulating the passivation quantity on the B-O defect by the H by using the current, thereby achieving a new stable state, wherein this state cannot return to the high compound state to influence the cell efficiency due to the illumination, so that the failure rate is reduced to within 1.5% under the standard light failure testing condition whenthe efficiency reduction degree of the mono-crystalline solar cell is within 0.07%. The technology disclosed by the invention is not limited to the mono-crystalline solar cell, and further comprisesmono-crystalline-like and polycrystalline solar cells, and the photoelectric conversion efficiency of the cell cannot be reduced by the light failure improved obtained on the polycrystalline solar cell. The technology temperature, the current and the time selected by the invention are easy to achieve and control; the technology is simple in method, obvious in effect, and capable of being compatible with the industrial production, and has high practical value.