In this study, we examine a competitive Nicholson blowflies model with time-varying coefficients and continuous time delays. In the case of coincidence degree theory, constructing appropriate Lyapunov functionals and using several inequalities, several conditions on the extinction, periodic solution, permanence, and global attractiveness of the system are derived. Finally, three examples with numerical simulations are presented to validate the practicability and feasibility of the obtained theoretical results.