Early age cracking of high water binder ratio concrete seriously affected the durability of concrete. The effects of super absorbent polymer（SAP） particles（mass fractions are 02%，03%，04%) on the early cracking resistance，mechanical properties and volume stability of concrete of high water binder ratio（mW/mB=05) were investigated. Water losing regularity of concrete was also studied by using evaporation experiment. The results show that SAP can effectively improve the early cracking resistance of the high water binder ratio concrete. When the mass fraction of SAP were 02%, 03% and 04%, the areas of early age cracking of concrete are reduced by 81%, 88% and 98%, respectively. Addition of SAP can significantly reduce water evaporation of concrete, inhibit its volume shrinkage, and does not decrease its mechanical strength.