The invention provides a sealed treatment apparatus for SAGD produced fluid, which includes, in a successively connected manner, a cyclone degassing and sand removing device, a cyclone dewatering device, and a pulse type electric dewatering device. The invention also provides a sealed treatment process for SAGD produced fluid with the apparatus. The process includes the following steps: (A) injecting the oil well produced fluid into the cyclone degassing and sand removing device to perform degassing and sand removal; (B) adding an oil-removal type demulsifier to the oil well produced fluid after the degassing and sand removal treatment; (C) injecting the oil well produced fluid in the step (B) into the cyclone dewatering device to perform primary dewatering treatment to obtain to-be-processed raw oil and oil containing waste water; (D) adding a dewatering-type demulsifier to the to-be-processed raw oil; (E) injecting the to-be-processed raw oil in the step (D) into the pulse type electric dewatering device to perform secondary dewatering treatment to obtain qualified raw oil and wastewater. In the method, a cyclone method is employed for treatment of the SAGD produced fluid, so that ultra-thick oil produced fluid is separated under a high temperature sealed condition to obtain qualified raw oil and recyclable purified water.