The invention discloses a computer vision-based method for automatically monitoring rehydration of unsalted dried sea cucumbers. The method comprises the following steps of: 1, rehydrating pretreated unsalted dried sea cucumbers; 2, acquiring rehydration images, recording body type data of the unsalted dried sea cucumbers in real time, and forming a unsalted dried sea cucumber rehydration geometric locus formed by body type area of the unsalted dried sea cucumbers and the rehydration time in real time; 3, performing curve fitting on the geometric locus and calculating a tangent slope of the fitted curve; and 4, judging whether the tangent slope of the fitted curve meets the rehydration standard; if the tangent slope meets the standard, finishing the rehydration; and if the tangent slope does not meet the standard, turning to the step 2. In the method, the rehydration images of the sea cucumbers are acquired by using a camera; the images are transmitted to a computer for analysis processing; and the analog curve of body type changes of the rehydrated sea cucumber is fitted so as to judge whether the sea cucumbers meet the rehydration requirements.