The Chinese strategy for launching a surprise attack on Taiwan is discussed at The Strategy Page. Some analysts think it's just a matter of time.
The Chinese probably aren't too concerned about our reaction since our economies are so interdependent they probably calculate (correctly) that if they can launch a successful assault on Taiwan before we have a chance to get a carrier battle group to the region that they will have a fait accompli over which we will not be willing to wage all out war.
There will follow grave diplomatic harrumphing, of course, but eventually the imperatives of commerce will cool tempers, and we will grudgingly accept the Chinese takeover (and subsequent executions) of the Taiwanese.
No doubt the biggest concern of the Chinese is whether they would be able to overwhelm Taiwan's defenses swiftly enough to preclude American involvement. This may be quite difficult to accomplish, for reasons discussed at Strategy Page.
It's interesting reading.