Compared the Q-switch characteristic of three kinds of electro-optic crystals (LiNbO3 , KD3P and KTP) , thepotential of KTP Q-switch is confirmed. We have also analyzed the sensitivity of transmission of KTP Q-switch to temperature changes and found that the two crossed identical KTP crystals can compensate the birefringence. Furthermore,the two-element configuration can guarantee the stability of the Q-switch and increase the dependability of the lasers.