The present invention relates to a phase-locked-free system and method for receiving a multi-formulation format compatible high-speed laser signal, which can significantly improve the compatibility of the communication format at a relay node in the existing laser communication network, decreases the price for the system upgrade, and reduces resource costs thereof. The system comprises a control instruction unit, a low noise high-gain optical amplifier, an optical switch, a filter, an optical delay interferometer I, an optical delay interferometer Q, a first balanced detector, a second balanced detector, an anti-code switch unit, a parallel-serial conversion unit, and a data processing unit. The control instruction unit is connected to the optical switch, the anti-code switch unit, and the parallel-serial conversion unit, separately; the low noise high-gain optical amplifier is connected to the optical switch; the optical switch is connected to the first balanced detector and the second balanced detector by means of the filter, the optical delay interferometer I, and the optical delay interferometer Q, respectively; the first balanced detector and the second balanced detector sequentially pass through the anti-code switch unit, the parallel-serial conversion unit, and the data processing unit and output an electrical signal.