Why my phone no power?

The first thing to do is figure out if this is a problem with your phone or not. Start out by checking these things in order.

1. The wall outlet. Verify you have power; if you have a multimeter check for the proper voltage, otherwise plug in something easy to see like a lamp.
2. The charger. Either try it with another device or try a different one.
3. The charging cord. Again, try charging something else or swap it for a different cord.
4. The charging port. Check inside for any dirt, lint or obstruction that could be keeping the plug from making contact. Check it with a magnifying glass and a bright light looking for bent or broken pins. Use some compressed air, a vacuum, and/or clean it out with 90% or higher concentration of isopropyl (rubbing) alcohol, an eyeglass cloth and a toothpick. Don't stick anything metal in the charging port unless you first disconnect the battery or you can short it out and cause yourself more damage.

Once you've gotten through this list, come on back and add a comment telling us what you tried and what you found.