When I import time-series 1 channel images.
In 3D view, the images are show as gray, but in tri-view they are showed as color images?

that is because you chose the wrapping with "channel", thus for the tri-view, the first, second, and third channels are displayed using the first three time points' information. In the 3D viewer, the time axis is used and thus the channel information is interpreted as the time info correctly.

So both displays are correct.

If your input image (any single time point) has three color channels, then you won't see this difference.