The invention relates to a slowly-closing check valve, which is used for solving the problems that a slowly closing mechanism of the existing check valve is relatively complex, and the service life is short. The slowly-closing check valve comprises a valve body, a valve clack, a rocking bar and a rotating shaft, a slowly closing mechanism which is used for inserting the rotating shaft is arranged in the valve body, the slowly closing mechanism has a first state enabling the rotating shaft to rotate slowly, a second state enabling the rotating shaft to rotate rapidly and a third state enabling the rotating shaft to slowly rotate until the valve clack is completely opened or completely closed. The slowly-closing check valve has beneficial effects that when the valve clack is opened or closed, the valve clack experiences a slow process, a rapid process and a slow process, the impact force of the valve clack when the valve clack is suddenly opened or closed is not too great, a product can arrive in place rapidly by virtue of intermediate rapid response, the product arrives in place slowly when the valve clack is opened in the final slow process, the impact on a sealing surface of the valve body is reduced when the valve clack is closed, the abrasion of the sealing surface is avoided, and a water hammer phenomenon is avoided.