A pit experimental investigations on elastic modulus of the dn160 steel-plastic composite pipe are carried out in the paper. The experimental results show that the elastic modulus of steel-plastic composite pipe is 10.93 GPa. In order to verify the pit experimental, buried-heating experiments are conducted. It was found that the deviation is within 6%. The excellent agreement indicated that the elastic modulus data by pit experiment are reliable and can be used as basic data for directly buried heating pipeline design.