Iam canceling my visa contract before1 year. I...

We would like to inform you that if your contract is terminated a year before the expiry of the visa, then in this case the worker is obligated to compensate the employer for the loss that he sustained as a result of the annulment of the contract, provided that the compensation amount does not exceed half a month's wages for a period of three months or the remaining period of the contract, whichever is shorter

And all of this unless there is a text in the contract that stipulates otherwise
You can inquire at the website of the UAE government on the following link: 
UAE Government Portal
. In accordance with the provisions of the Labor Law:

Article 116
Where a contract is revoked by the worker for reasons other than those specified in Article (121), he shall be required to compensate the employer for any damage the latter sustains as a result, provided that the amount of compensation shall not exceed half a month wage for three months or for the remaining period of the contract, whichever is shorter, unless otherwise stipulated in the contract.