The invention provides an opening-closing device used for a high-pressure safety valve. The opening-closing device comprises a valve body, an internal connecting tube, an opening-closing part and a performing mechanism, wherein the valve body forms a main body of the safety valve; an inlet of the valve body communicates with a working medium; the internal connecting tube is positioned inside the valve body; one end of the internal connecting tube is in sealing connection with the inlet of the valve body; the opening-closing part is positioned inside the valve body, and is connected with a pivotal shaft at the other end of the internal connecting tube; the performing mechanism is positioned on a combined part of the internal connecting tube and the opening-closing part; when the performingmechanism is not triggered, the internal connecting tube is in sealing connection with the opening-closing part; and when the performing mechanism is triggered, connection between the internal connecting tube and the opening-closing part is released. According to the technical scheme adopted by the invention, zero leakage is realized through the partial load design of the opening-closing part while operating force needed for the performing mechanism can be greatly reduced, so that good foundation is laid up for improving safety and reliability of valve operation.