In this article, we first discussed the concept of analog simulation and numerical simulation. Then we compared the three most important scientific research methods: observation, theoretical study and numerical simulation, to develop a better understanding of their advantages, restrictions and their interrelationship. In section 3, two basic types of numerical simulation and their basic ideas were introduced. We concentrated here on MHD simulation. Several important components of MHD space numerical simulation were introduced. These components are the core of the simulation which we have to deal with in simulation practice. Then through the study of a practical simulation problem: the one-dimensional of shock-tube problem, we integrated the content discussed in the former part of this article to form a whole view of numerical simulation. This helps us to achieve the basic ability to perform a simple numerical simulation.

This article is only an introduction to MHD numerical simulation in space physics. Though most of the basic ideas of space numerical simulation have been discussed, much more work is needed before we can really produce successful simulation programs and apply them in scientific studies. Much difficulty can be met in this process, but the fruit after this hard work is much more than worthwhile.