The client must be fully synchronized before use.In order to speed up network synchronization you can download an offline package of the blockchain data up to a certain block height. This means the client will only need to sync the additional blocks from the NEO network rather than the entire blockchain.
We recommond you downloading the offline package here for neo-cli and neo-gui v2.7.6 or above.
More info：https://docs.neo.org/docs/en-us/node/syncblocks.html
客户端运行时会自动同步区块数据，打开钱包时也会自动同步钱包数据，当同步完成后才可以正常使用客户端以及查看钱包内资产。 由于区块链数据庞大，初次同步时等待时间通常很久。如果已经不是初次运行客户端，并且想快速同步到最新高度，可以直接下载最近的离线增量数据包来加速同步。
建议2.7.6及以上版本的neo-cli和neo-gui下载本页的离线数据包进行同步。
详情：https://docs.neo.org/docs/zh-cn/node/syncblocks.html