Main chain and sub chain transaction method for block chain, and block chain network
The invention discloses a main chain and sub chain transaction method for a block chain. The method comprises the steps that a first node writes a capital injection parameter provided by a sub chain capital injection person into a first smart contract by calling a capital injection function in the first smart contract of a main chain; a second node writes a hash value h, a first account address, ato be extracted sub chain token number and a valid period provided by a sub chain owner into a second smart contract of a sub chain; the first node calls the second smart contract in the sub chain according to an initial number r in the valid period to obtain the to be extracted sub chain token number; and after extraction operation of the first node is confirmed, the second node calls the firstsmart contract in the main chain according to the obtained initial number r to obtain a corresponding quantity of main chain tokens locked in the main chain by the sub chain capital injection person.The invention furthermore provides a block chain network, which can realize decentralized transaction and exchange of the main chain and sub chain tokens.