Valve linkage device, drill rod shearing method and blowout preventer control device

The invention discloses a valve linkage device. The valve linkage device comprises a linkage execution mechanism, a second pressure source and a logic sequence valve, wherein the linkage execution mechanism is used for controlling a bypass valve to be in an open position when a shear ram valve is in a closed position, so that a first pressure source outputs first pressure to a shear ram blowout preventer, the logic sequence valve is installed on a pipeline between the second pressure source and the shear ram blowout preventer and used for enabling the second pressure source to output second pressure to the shear ram blowout preventer when first operation is executed. The invention further discloses a drill rod shearing method and a blowout preventer control device. The situation that whenan operator needs to close shearing under the highly tense condition, the bypass valve is not opened or forgotten to be opened, so that the pressure of a shear ram is insufficient, and a drill rod cannot be sheared off can be