The GA-BP neural network and the orthogonal test design method were used to analyze the sensitivity of affecting factors of the bearing capacity of PHC piles in a area of Fujian province, in which the pile's bearing behavior belongs to end bearing-friction type and the pile shaft teems with mucky soil and residual cohesive soil layers primarily. The main conclusions are as follows ; ① accord- ing to priority,the sensitivity order of the influence factors on vertical bearing capacity of the single pile are pile diameter,the weighted average of pile shaft resistance valuea,resting stage,pile length, buried depth of pile, permeability coefficient and final pile static pressure; ②the contribution of pile diameter and pile shaft resistance value to vertical bearing capacity of the single pile is the largest, resting stage is in the next place which influence is also very notable,so the pile test time should not be in advance blindly,otherwise the pile test results would be affected objectivity.