A three-dimensional elastoplastic finite element model is used to analyze the behaviors of cast-in-situ concrete thin-wall pipe piles (referred to as PCC)under lateral loading; and the rationality of the model is verified through comparisons between calculations and field test results. Using this model

the factors such as pile length

pile diameter and modulus ratio of pile to soil that affect the behaviors of PCC piles are also analyzed. All results show that: when the ratio of pile length to pile diameter is less than 8

the pile behaviors as a rigid pile

which makes a whole incline; otherwise

the pile behaviors as a long elastic pile and the pile responses mainly focus on upper part about 1/3 of the pile length. When diameter becomes larger

the lateral deflection of pile becomes smaller

but the pile maximum moment becomes larger and the site of maximum moment becomes lower. At last

with the ration of pile modulus to soil modulus increment

the lateral deflection decreases and the maximum moment becomes increscent.