Steel lined reinforced concrete penstock built on the downstream surface of dam is used in TGP's power station.This kind of penstock is of a novel style.There fore,How will be the stress and strain statuses of penstock occurring cracks and under the action of temperature load in the operating period is still one of i mportant problems not being solved.By means of simulating model experiment and n onlinear fininte element method,the research on temperature stress and strain un der the action of temperature differences between the inner and outside of steel lined reinforced concrete penstock was performed.The reliable results were ob tained,and primary basis for pipe line design was provided