The invention discloses a parallel flow evaporator and an anti-freezing method thereof. The method comprises multistage anti-freezing programs. During normal refrigeration of an air conditioner, when the primary surface temperature TA of the indoor parallel flow evaporator is less than or equal to 0 DEG C, the primary anti-freezing program is started, an electromagnetic valve is opened, and the evaporation temperature of the parallel flow evaporator is raised to defrost the evaporator; after the opening time TN of the electromagnetic valve achieves a set time Tn, the surface temperature TA of the indoor parallel flow evaporator is detected again; when the TA is more than or equal to a set temperature Ta of the indoor parallel flow evaporator, the primary anti-freezing program is finished, and the electromagnetic valve is closed; and when the TA is less than 0 DEG C, a secondary anti-freezing program is started, and a compressor of the air conditioner is closed. The parallel flow evaporator has a simple and durable structure; and the anti-freezing method can implement anti-freezing of the parallel flow evaporator more intelligently and friendlily, reduce frequent starting of the compressor in a refrigeration loop, and ensure the refrigeration effect of the air conditioner.