For regular canonical system of first order differential equations, we associate sym¬metric linear relations. Also, we define the minimal and the maximal relations for this case and construct the generalized resolvents related to the selfadjoint extensions for these symmetric relations defined in Hilbert space H or larger than the given space H. One can construct the eigenfunction expansions for the systems we are interested in and the so-called Weyl-coefficients which are the main idea to construct the spectrum of the symmetric relations. We may illustrate this case by giving some examples.