The theoretical and experimental study of fiber grating multi-point sensing made. By means of defining the signal resolution factor of multi-point sensing, the condition of signal resolution has been analyzed, the mathematical expression of the sensing principle of multi-point temperature and strain have been given and the system multiplexing capacity by dominated optical source bandwidth has been researched. The fiber grating multi-point sensing network system with some features has been designed and realized. By using this sensing network system, the multi-point sensing experimental analyses and theoretical verification of temperature and displacement sensing have been completed in the two channels of the sensing network system. The experimental results are in good agreement with the theoretical analyses of multi-point sensing.