The invention provides a dinucleotide 
prodrug being novel in structure, and further provides a preparation method of a dinucleotide 
prodrug, and an application of the dinucleotide 
prodrug to preparation of drugs for treating 
viral infection, particularly to drugs for treating 
hepatitis B 
virus (HBV) infection and HBV relevant liver diseases. The dinucleotide prodrug compound can notably improve the target properties in the liver, can improve the accumulation capacity in liver locations, can further effectively improve the 
drug effect and activity, can reduce the use dosage, and can further reduce the toxic and side effects. Experimentation on animals indicates that after being absorbed in bodies, the dinucleotide prodrug compound can be rapidly distributed in extravascular tissue from a 
central compartment, and can be concentrated massively in the liver, and low dosage of the dinucleotide prodrug compound can be observed in other tissue. The dinucleotide prodrug compound provided by the invention also has the advantages of being high in 
biological availability when being taken orally, good in stability in the 
stomach, and long in life 
in vivo.