How to stop program while Servo is rotating
How can I implement this? Is it possible to read Servo's statement?


No, it is not possible. When you do a servo.write() it just changes the PWM duty cycle. It's then up to the servo to use that to set its position. The Arduino has no concept at all of the current position of the servo.


  Btw, I don't want to put delay after write(), so other than that strategy.


The only other way, besides delaying or otherwise using millis() to wait for a predefined period after your write would be to implement some form of feedback between the shaft of the servo and the Arduino. Maybe a potentiometer, or rotary encoder would do the job.