Abstract: In order to improve the fracturing effect of ultra-low permeability reservoirs,by taking G644 block as an example,through " four-property" relationship research,thestandards for reservoir evaluation were established,the fracturing horizons were optimized and the main factors influencing the fracturing effect were analyzed.And therefore,the reservoir development situation was given out,and the liquid producing capacity was increased.The results indicate the reasonable fracturing timing is an important guarantee to improve the fracturing effect.