So when will china deploy practical laser guns in warships? Any idea or suggestions?
That is an unanswerable question. At this time, laser weapons are mostly still in the testing and prototyping stage. We're getting there, but it's not yet matured to a point that it can reliably and consistently replace an existing defense system.
So your question is inviting speculation that has no basis on factual observations or reporting that we've seen so far. Will the PLAN use lasers at some point? Very likely. Is the technology ready enough for us to know a potential date? Not even close.