In two frame of reference with relative motion, observing each other's clocks and rulers is an important method to judge whether they have changes in time rate and length. The light reflection device (including light source, mirror opposite the light source and observer) is a suitable clock and ruler. However, people have been living in low-velocity motions world, so it is easier to cause some confusions. For example, because the velocity of light is limited, in a high-velocity train it is impossible for a directed single or a series of photons to reach the mirror opposite the device and the mirror is not in the expected rest position. It can only succeed when it emits the spherical light waves. However, at this time, both high-velocity and rest observers can detect the same light path and time. On the other side, if the device is set on the ground, both high-velocity and rest observers also detect the same light path and time which are both decreased. Therefore, the time rate is faster and the length is longer than that on the train. The article uses the physical field reconstruction to study the physical process of high-velocity motion, and points out that the geometric center of the light emitting can be used as an absolute rest frame of reference to analysis. The proposed new concept of space-time can deal with the Twin Paradox without contradiction, and prefectly explain the high-velocity physical phenomena observed.