in http://omnichest.info
i found address show different amount, is this mean this address can receive multi coins.
example can i send bcc ot usdt to this address?
OMNI chain works "kind of" similar to that of Ethereum chain as it is a meta-asset layer and smart-contract platform. The only difference being, OMNI runs on top of the Bitcoin blockchain.
Just as someone can own any number of ERC-20 tokens on an ethereum address, you can do that too within the OMNI protocol. The "multi coins" you are seeing are just tokens that are run on OMNI protocol.
Although there are others like BCG and LTC that don't follow this format so for those it won't work so you need to be careful with it. And also, it's not very safe to put all your coins on one private key.
They are not forked coins, but independent tokens similar to Ethereum's ERC-20 tokens.