Model checking is an automatic approach to verification. For model checking the system (model) is given as Kripke structure and the specification is written in a temporal logic. Hyper2LTL is a new temporal logic that extends HyperLTL by the quantification over sets of traces. It can express second-order hyperproperties, such as common knowledge. Since model checking Hyper2LTL is in general undecidable, were strict the models to be acyclic and analyze the complexity in the size of the model. We show that Hyper2LTL model checking is decidable on acyclic models. It is in PSPACE on tree-shaped models and in EXPSPACE on acyclic models. Additionally, we show that for a powerful fragment of Hyper2LTL, called Fixpoint Hyper2LTL_fp, model checking is P-complete on tree-shaped models and EXP-complete on acyclic models.