Ordered structures in thin films of ABC triblock copolymers are studied experimentally and theoretically in order to be applied to fabrication of nanoscale electronic devices. A field-theoretic simulation method based on the self-consistent field theory is used to generate useful nanopatterns starting with a random configuration of compositions. The main parameters for the phase stability, such as Flory interaction parameters, total chain size, compositions, film thickness, and surface interactions, are considered as controllable variables in the present analysis. By using some typical triblock copolymers, nanopatterns observed in experiments are comparable with those in the simulation.