Most P2P algorithms based on distributed Hash table（DHT） faced Churn

which was caused by the continuous process of node joining and failure.A Churn evaluating model was proposed and its formulized description

which could give some important instructions for analyzing current P2P algorithms and designing new algorithms.Using this model

a simulation including three P2P algorithm Chord

Kelips

and Tapestry was done.The experiment results show the capability of these algorithms under Churn

the advantage of Chord than others

and the most important factor affecting Churn.