Low density polyethylene（LDPE） modification to improve low temperature performance of bitumen is still controversial at present. In order to accurately evaluate the low temperature performance of LDPE modified bitumen， bending beam rheometer tests were carried out to obtain stiffness modulus（S）， modulus change rate（m）， and then the low temperature accumulated stress，dissipation energy rate were calculated. Based on dynamic shear rheometer test and the principle of time temperature equivalence， the master curve of complex modulus， the glass transition modulus and crossover frequency were obtained. Based on the force ductility test， the tension-ductility curve was measured， and the yield strain energy， breaking work and other index values were obtained. The results show that with the increase of LDPE content， the S of the modified bitumen increases， the m decreases， the low temperature cumulative stress increases， the dissipation energy rate decreases， the glass transition modulus increases and the crossover frequency decreases， which shows that the low temperature performance decreases. However， the breaking work required for the failure of LDPE modified bitumen is greater than that of base bitumen， which shows the better low temperature performance of LDPE modified bitumen from the point of view of failure energy. Therefore， low temperature performance of LDPE modified bitumen may be underestimated only based on the evaluation index of S， m. So breaking work should be considered as one of the supplementary evaluation indexes.