I get that crak when my part stuck in mould. Can you help how to repair it?
Should I make patch underneath to reinforced also?
Thanks

If you're trying to leave the clear finished part surface without doing an ugly repair, just hand laminate 2 plies of the same 200g material over the back with the fibers going +/-45 degrees to the crack.  Extend the patch 50mm past the extents of the crack.  You can do this with a brush and roller and if there's no load on the part (and the forces that initiated the crack are never likely to happen again) drilling a hole will only add a cosmetic issue to fix.  Half a mm of laminate is tough to scarf. 

If you are going to paint the part, do the plies on the back and then once that's cured, lightly grind out the crack (making a scarf joint 30-50 mm beyond the crack like in Hanaldo's picture) and patch with two more plies from the front and then sand/grind it fair once its cured.  You'll want to use normal laminating epoxy (not infusion stuff) for this because it is thicker and will stay in the fabric.  Peel ply helps too if you have it.  You may want to post cure the patch if the part is going to be dark colored and used outdoors.  More on post-curing elsewhere on this forum.