What? You didn't check the hack list? It said USA rom. It work on emulator but didnt work on flash cart. So I want to know why it only work on emulator and not flash cart.
You are the one asking for help so it is your job to tell us what you are using, can also help to note what system it is for as a lot of things in ROM hacking are reasonably system specific, especially when it comes to debugging these sorts of issues. This is to say what patch and preferably where you got it (going by previous posts of yours here it could have been from some random forum post or maybe even a premade ROM). You would also do well to note what you are trying to run it on -- some fly by night R4 named thing on the DS vs say one the nice flash carts from a well known maker, or one of those weird SD launchers for the DSi/3ds. Equally do you have cheats running?
Basically make the life of the person that would be helping you as easy as possible short of sharing the ROM.
Anyway what does no$gba debug say when you try to run it? http://problemkaputt.de/gba.htm
if it starts spitting errors about bad instructions, BIOS/SWI calls or similar then that is one thing.
GBA and DS ROMs not working on hardware for a thing ROM hackers will fix is something of a rarity (there are no inaccurate emulator only tricks like we saw for the SNES, no HD texture replacement in emulator like we commonly see on the N64 and gamecube) and most emulators are good about a lot of things here. There are still some things though (say compression not being compatible with the graphics side of things, easy to do for new hackers) and there could be some weird timing issue.
99% of the time though it is someone patched the wrong ROM, their flash cart/running method is bad, they left cheats on and it messed something up with the hack or some combo of the lot.