How can I know if the blockchain network is with all fake nodes.What if i create my block network with all my fake nodes to validate transactions?
-- dropping this in the answer secton, cause too many characters for comment section ---
certainly you can create your own blockchain, and create all your own fake nodes. But why would someone join your network? What is the value?
Bitcoin blockchain is currently managing ~19 billion US$, and must assure, not too many fake nodes "come in". In this case, the network is protected by +5000 other nodes, and many mining nodes to ensure proper functionality of the network. I recommend reading "https://bitcoin.org/en/how-it-works" or it's translations, especially the link to the mining section, and "Going down the rabbit hole". As this here is more a development oriented area, it might be better to discuss such question in a forum like "https://bitcointalk.org/index.php". Hope this helps :-)
It's unclear from your question whether you're talking about creating a new blockchain/network. If yes, all depends on how you choose to implement things. In what follows, I assume you're talking about the Bitcoin blockchain (though the answer may apply to other cases).
In Bitcoin, a concept of a "full node" exists. This is a node that downloads and verifies all blocks and transactions, and verifies them autonomously.
If you run a full node yourself, it doesn't matter what your peers are. As long as you occasionally get connected to at least one honest node, you will learn about the best chain from them, and validate it yourself. All other node can behave in any way they like - including censoring transactions, or sending you invalid blocks.