In this paper, a class of singular Sturm–Liouville problems with transmission conditions at finite interior points is studied. The equation, center and radius of Weyl circle are given. The necessary and sufficient conditions for the function $$ m(\lambda ) $$ , which is in the Weyl circle, are established. The definition of Weyl function for singular Sturm–Liouville problems with transmission conditions in the case of limit circle is given, and the properties of Weyl function are discussed.