The invention discloses a smart pipeline type automatic dehydrator of the oil tank and pressure pot, comprising an entrance flange, an outlet flange, a honeycomb duct, a major detecting controller, a minor detecting controller, a major filter, a minor filter, a vapor pipe, a temperature controller, an adjusting valve and a drain-trap. The entrance flange of the honeycomb duct is connected with the spot oil tank, and the outlet flange is connected with the adjusting valve; the sensors of the major and minor detecting controllers are respectively connected with the honeycomb duct, and the major and minor filters are respectively covered on the sensors of the major and minor detecting controllers, the signal outputs of the major and minor detecting controllers are connected with the adjusting valve. Because the dehydrator is connected with the oil tank by the mounting flange, when the size is not suitable, the problem can be solved by adding a converting joint, and the mounting is very convenient. Meanwhile the honeycomb duct adopts a streamline structure, and completely without circulation dead angle. While dehydration, the solid impurity settled in the bottom medium of the dehydrator can be discharged with water without budget in the dehydrator, and the invention has a self rinsing function, and does not need periodical rinsing. The invention is suitable for the automatic dehydration field of oil tank, liquefied gas tank and pressure storage tank of chemical product.