1. A multivariate space processing method, comprising: degenerating multivariate data into three predetermined variates; determining a reference variate to serve as a reference among the three variates; acquiring a first two-dimensional space formed by the remaining two variates when the reference variate takes a first value; acquiring a second two-dimensional space formed by the remaining two variates when the reference variate takes a second value; and computing a matching between the first two-dimensional space and the second two-dimensional space.