For the practical teaching of smart grid information engineering undergraduate specialty, carrying out the construction of microcomputer principle digital virtual laboratory is of great significance to cultivate compound engineering application talents for the smart grid industry. The constructed microcomputer principle virtual laboratory uses three kinds of 8086 visual assembler and debugging software (CLAB, STAR and EMU8086), as well as EDA software which supports 8086 simulation operation to carry out hardware and software system design. Based on the virtual laboratory, the topics of smart grid specialty’s course design or graduation design can adopt the principle of combining with actual smart grid technologies. The practical application of the virtual laboratory is introduced by taking a design case of definite-time over-current relay protection. This teaching method of combining theory with practice can enhance students’ cognitions of building strong smart grid and new-type power system in China. The teaching practice in recent years shows that the teaching effect of the microcomputer principle virtual laboratory is remarkable, and it has practical value in cultivating and improving students’ practical innovation ability, which is worth further research and practice.