Syllogic safety door hook comprises coupler body, locking lever, first spring, accuse pole and second spring. Shaft hole, the first trough are established in a hook mouth ora terminalis to the coupler body, in addition an ora terminalis portion that limits, a locking lever ora terminalis is equipped with the first bolt that can move along the first trough, and when first bolt moved to the primary importance of the first trough, locking lever end in addition was positioned spacing portion and seals hook mouth, then enables the locking lever and hold in addition and be in spacing position when first bolt moves to the second place of the first trough, first spring actuates first bolt and keeps in the primary importance and actuate other end of locking lever keeping in spacing portion, the accuse pole can restrict first the bolt in the primary importance with main shaft pin joint an in shaft hole, order accuse pole when swinging to the third position to actuate the accuse pole with the second spring and keep in the third position, in order to ensure locking lever shutting hook mouth. When desiring to open this hook mouth, the pole of operation accuse earlier break away from the third position, can stimulate the locking lever and make first bolt remove to the second place, then it, it is rotatory towards the dog hole to actuate the locking lever for it opens the hook mouth mode to constitute the three-section.