Cement fineness, cement hydration and concrete cracking are closely related. Influence of cement fineness on hydration heat and hydration rate of cement was investigated using microcalorimetry. Early age shrinkage and early age cracking of concrete prepared with different fineness cement were determined using non contact laser displacement sensor and centralized constrained plate method, respectively. The test results show that with increase of cement fineness, hydration heat and hydration rate are increased, and time to peak of hydration is reduced. Increasing the specific surface area of cement causes higher shrinkage and unit crack area at early age, but reduces rate of water evaporation and maximum crack width of concrete. According to the research results, it is suggested to set an upper limit value of the cement fineness in concrete engineering.