How can i fix this problem ?.
A photo will be helpful as well.
Your problem stems from the relay and/or the motor. You can verify this by temporarily substituting an LED (with current limiting resistor) for the relay coil at the output pin of your Arduino.
Use the stealth search box at the upper right and look for terms such as 'LED garbage', 'LED weird', etc. There are lots of previous threads about this, typically dealing with the power.
Don