The invention provides a virtual currency transaction validation method based on block chain multi-factor cross-validation to solve the double-spending problem that virtual currency based on block chains are liable to 51% attacks and thus generates transactions. The method queries and backups a history block chain branch periodically, organizes confirmed transaction information into a hash chain list array which is easy for querying, and avoids branch transaction information losses induced by block chain evolution. During a virtual currency transaction, the method not only checks payer information, recipient information, a fund source, a currency transaction amount and the like recorded in a current main block chain, but also queries a backup branch block chain to check whether the current transaction and a history transaction on the branch block chain have the same fund source. If any transaction does not pass the check, a miner gives an alarm over the whole network about the transaction, so that the method can avoid the double-spending problem induced by illegal transactions.