The invention discloses a detection error-proofing method and device for a high-vacuum valve of a die-casting die. The method comprises the steps that when the high-vacuum valve is opened, a vacuum machine vacuumizes the die, the high-vacuum valve is detected to be opened through a travel switch arranged in the vacuum valve, and an opening signal is sent to a PLC in the vacuum machine; if the high-vacuum valve is not returned to be closed completely within the set time, a returning-closing completion indicator light is turned off, a signal is sent to control an intermediate relay to give an alarm, and an error-proofing alarm lamp is turned on; and an operator can perform detection through a manual-switch vacuum valve knob on an operation panel of a die-casting machine at the moment. The method and device have the advantages of being stable, reliable and durable in system, good in error-proofing performance, easy to operate, convenient, practical and capable of effectively conducting real-time detection error-proofing on the high-vacuum valve of the die-casting die.