Random fiber lasers have attracted extensive attention due to their rich physical properties and wide applications. Here, a novel random fiber laser (RFL) using a cascaded fiber loop mirror (FLM) is proposed and presented. A cascaded FLM with ten FLMs is simulated by the transfer matrix method and used to provide the random feedback. Multiple spikes are observed in both the simulated and measured reflection spectra. The RFL operates in a single longitudinal mode near the threshold and a time-varying multi-longitudinal mode at higher pump powers. The RFL exhibits a time-varying radio frequency spectrum. The Levy-Gaussian distribution transition is observed as in many RFLs. The operation mechanism of the lasing longitudinal modes and the impact of complex mode competition and mode hopping on the output characteristics are discussed through experimental and theoretical results. This study unveils a new artificial random feedback structure and paves a new way for the realization of RFLs, which should be a novel platform for multidisciplinary studies in complex systems.