With the large finite element software ANSYS,this paper establishes the single pile finite element model based on a 50 000 DWT high pile wharf.Calculation and analysis of the stress release at the damage and the influence of the damage on the horizontal bearing capacity in pile integrity detection in PHC pile are done.The results show that the stress release of PHC pile at the damage is obvious,the stress change at the damaged is significant,the rule of the stress change and the stress concentration factor are not related to the stress level of the pile.The pre-stress in PHC pile can improve the ability of cracking resistance of the damaged pile greatly.Stress concentration is significant at the damage,when the pre-stress level is higher,the stress change is greater at the damage.The most unfavorable section moves to platform damage.