The invention relates to a dual-long-loop structured filter-free wideband-tunable photoelectric oscillator. By the dual-long-loop structured filter-free wideband-tunable photoelectric oscillator, the problem that an existing optical/electrical filter cannot be adopted to achieve large-range frequency tuning of the photoelectric oscillator while signal single-mode output is ensured is mainly solved. A laser (1) is connected with a strength modulator (3) through a polarization controller (2), the strength modulator (3) is connected with an optical coupler (5) through a long optical fiber (4), the optical coupler (5) is connected with a photoelectric detector (6) through an optical fiber and respectively two adjustable delay lines (7), the two photoelectric detectors (6) are combined to a path by an electric synthesizer to be connected with an input end of a power amplifier, and an output end of the power amplifier and the strength modulator are separately connected with a power divider. The dual-long-loop structured filter-free wideband-tunable photoelectric oscillator has the potential of rapid frequency tuning, and the tuning method is simple.