Low temperature performance and correlation between PG index and 25℃ penetration， as well as PG index and 5℃ ductility of SBS modified asphalts was evaluated by outputting Person coefficients and linear fitting. The results show that low temperature performance of SBS modified asphalts is improved compared with matrix asphalts， TB+SBS modified asphalts and rubber powder modified asphalts with high proportion of rubber powder could reach the best low temperature performance. 5℃ ductility has a very low correlation degree with PG index， which is limited to evaluate the low temperature performance of most SBS modified asphalts. Correlation of 25℃ penetration and PG index is higher than correlation of 5℃ ductility and PG index， but it needs further study.