mysql crashed, after start again, the new data lost, only old records of some day ago
Do you know how to fix this? 


Yes, Apply the latest backup.

If you can not do that because you do not take backups - look please for a job where you are not responsible for managing data. Backups is "professional databases for beginner admins, day 1, hour 1". Fundamental Like not driving a car totally drunk level of fundamental.

That being said, this sounds "crazy". As in - I am sure you overlook something. This is not a behavior I would expect on a crash UNLESS it runs on a VM and was rolling back to a backup or fixed start state.... corruption DOES sometimes make things bad or result in lost data, but rarely in a consistent state some days back. I would investigate whether you have a larger problem. I remember a company loosing money because the (not so smart) admin had set up vm's to roll back to a known state in case of a backup... which wiped access keys that can not be recovered to some serious funds (http://siliconangle.com/blog/2011/08/01/third-largest-bitcoin-exchange-bitomat-lost-their-wallet-over-17000-bitcoins-missing/). I would expect your problem to be something along this line. A rollback without corruption to a state some days ago is very very unlikely.