The changes of electrical resistivity and autogenous shrinkage of Portland cement pastes with water to binder ratio(by mass) of 03 and with different contents(by mass) of fly ash from 0% to 20%, 40% were investigated. The electrical resistivity was determined by a non electrode resistivity apparatus. The autogenous shrinkage was determined by digital dial gauge using a prismatic specimen. The results show that fly ash has a great influence on the changes of electrical resistivity and autogenous shrinkage of the cement pastes. The electrical resistivity of the cement paste increases before setting and decreases after hardened with the increase of content of fly ash. At the same age, the autogenous shrinkage of the hardened cement paste decreases with the increase of content of fly ash. There is a positive correlation between the electrical resistivity and autogenous shrinkage for the hardened cement pastes at the early age.