PIC capture interrupt not triggering at 0.65v
I connected pulse input to CCP1 pin( capture1 pin), maximum and
  minimum volt of pulse is 2.5v and 0.65v


The CCP1 input has a Schmitt-trigger on it, which requires a voltage swing of at least 0.2Vdd to 0.8Vdd (= 1V to 4V when Vdd is 5V). If your signal is only going up to 2.5V then the CCP1 signal will stick low and input pulses will be ignored. 



Your circuit diagram shows a PC817 optocoupler with 3.3k pull-up resistor. If being driven properly it should be producing ~0.2V to 5V. You should find out what is causing the reduced voltage swing and correct it.