Berry geometric phase and quantum transition

For the emergence of Berry geometric phase,we analyze the relevant physical background condition of the weak transitions among quantum energy-levels. We elaborate a further discussion on the internal relationship between the strict obtainment of Berry geometric phase and the weak transitions. Our st udy shows that the strict obtainment of Berry geometric phase is the natura l result of the adiabatic limit effect of weak transitions among quantum en ergy-levels. These transitions occur inevitably during the evolution proces s of quantum system.