Because of magnetorheological (MR) dampers’ mechanical simplicity, high dynamic range, low power requirements, large force capacity and robustness, they are the most promising devices for structural vibration control. But this paper uses MR dampers’ damp characteristics to complete a function of short time delay, and the damper’s volume is smaller than the other dampers that have been applied for commercial uses. This paper discusses two types of structures for time delay, gap structure time delay device and holes structure time delay device. In order to estimate the two kinds of devices’ delay time, mathematical modeling and experimental testing are built in this paper. From the test results, we know that holes structure does not always implement theoretical delay time, but the gap structure can complete the time delay function satisfactory. For judging whether the time delay device can work normally under different circumstance, the time delay device with gap structure is tested in a change temperature field from -40 °C to 55 °C.