The invention discloses a return oil collector for detecting a hydraulic vibration control valve on line. The return oil collector is characterized in that the return oil collector is a hollow square cylinder body, wherein oil inlet adapter seats of 7 to 9 different specifications and a chief oil return hole are arranged on the wall of the square cylinder body; the chief oil return hole is connected with an oil tank through a chief return oil pipe; and the oil inlet adapter seats serving as oil inlets are respectively communicated with the corresponding overflow pipes on a hydraulic vibration control valve detection platform through pipeline threads. By the return oil collector, the number of the overflow pipes is reduced, and problems caused by arranging and connecting pipelines, particularly pipelines of equipment with a large number of complex overflow or return oil pipelines are solved; an on-line detection platform and an oil tank separation can be placed in different libraries; and the return oil collector can be taken and placed at any time, is easy to replace after being damaged, and is simple, practical and safe.