Chloride and alkalinity in pore solution expressed directly from cementitious materials under various influencing factors including mw/mc, age, chloride addition and carbonation exposure were investigated by ion chromatography and pH meter.It is found that the content of free chloride decreases with increase of mw/mc and decrease of chloride addition. The rate of combination of chloride increases with time and decreases with free chloride content in pore solution. The effect of carbonation on the dissolved chloride content in pore solution is great. For cement mortar or paste with different mw/mc(0.5 and 0.7) and chloride addition(0, 0.5% and 1.0%), complete carbonation can increase the amount of free chloride in pore solution 2 to 12 times. Furthermore, the amount of chemically combined chloride is lowered by 27% to 54%, and the pH value decreases from values in the range between 13.19 and 13.47 to values in the range between 7.67 and 8.10. It can be concluded that, in addition to lower the pH value of the pore solution, carbonation will release more free chloride from the hydration products into pore solution and the internal chemical environment of concrete is changed considerably.