A service execution method, wherein a data recording system comprises at least two first-type blockchain networks and one second-type blockchain network, wherein at least one node in each first-type blockchain network is managed by a designated manager, wherein at least one node in the second-type blockchain network is also managed by the designated manager, wherein: when data to be stored is submitted to any first-type blockchain network, the first-type blockchain network writes a first-type blockchain transaction containing the data to be stored into its own blockchain; and any node managed by the designated manager in the second-type blockchain network broadcasts a second-type blockchain transaction containing a transaction hash of the first-type blockchain transaction and a network identifier of the first-type blockchain network to the second-type blockchain network, wherein the second-type blockchain transaction is written into a blockchain of the second-type blockchain network; wherein the any node managed by the designated manager in the second-type blockchain network is further configured to: receive a first-type transaction hash as a transaction hash, sent by a user, of a to-be-read first-type blockchain transaction, the first-type transaction hash being the transaction hash of the first-type blockchain transaction; query the second-type blockchain transaction containing the first-type transaction hash, read the network identifier from the second-type blockchain transaction, read the first-type blockchain transaction corresponding to the first-type transaction hash from the blockchain of a first-type blockchain network corresponding to the read network identifier; and return the read first-type blockchain transaction to the user; wherein the service execution method comprises the following: receiving, by a service device, a service request sent by the user, wherein the service device is a device managed by a designated service party; performing data analysis on first-type blockchain transactions in a blockchain of each first-type blockchain network based on a predetermined data analysis model and the service request to obtain a service execution policy that matches the service request; and executing a service for the service request based on the service execution policy. when data to be stored is submitted to any first-type blockchain network, the first-type blockchain network writes a first-type blockchain transaction containing the data to be stored into its own blockchain; and any node managed by the designated manager in the second-type blockchain network broadcasts a second-type blockchain transaction containing a transaction hash of the first-type blockchain transaction and a network identifier of the first-type blockchain network to the second-type blockchain network, wherein the second-type blockchain transaction is written into a blockchain of the second-type blockchain network; wherein the any node managed by the designated manager in the second-type blockchain network is further configured to: receive a first-type transaction hash as a transaction hash, sent by a user, of a to-be-read first-type blockchain transaction, the first-type transaction hash being the transaction hash of the first-type blockchain transaction; query the second-type blockchain transaction containing the first-type transaction hash, read the network identifier from the second-type blockchain transaction, read the first-type blockchain transaction corresponding to the first-type transaction hash from the blockchain of a first-type blockchain network corresponding to the read network identifier; and return the read first-type blockchain transaction to the user; receive a first-type transaction hash as a transaction hash, sent by a user, of a to-be-read first-type blockchain transaction, the first-type transaction hash being the transaction hash of the first-type blockchain transaction; query the second-type blockchain transaction containing the first-type transaction hash, read the network identifier from the second-type blockchain transaction, read the first-type blockchain transaction corresponding to the first-type transaction hash from the blockchain of a first-type blockchain network corresponding to the read network identifier; and return the read first-type blockchain transaction to the user; wherein the service execution method comprises the following: receiving, by a service device, a service request sent by the user, wherein the service device is a device managed by a designated service party; performing data analysis on first-type blockchain transactions in a blockchain of each first-type blockchain network based on a predetermined data analysis model and the service request to obtain a service execution policy that matches the service request; and executing a service for the service request based on the service execution policy. receiving, by a service device, a service request sent by the user, wherein the service device is a device managed by a designated service party; performing data analysis on first-type blockchain transactions in a blockchain of each first-type blockchain network based on a predetermined data analysis model and the service request to obtain a service execution policy that matches the service request; and executing a service for the service request based on the service execution policy.