The invention provides an air-cooled frostless horizontal refrigerator and a manufacturing method thereof. The refrigerator comprises a refrigerator body, the refrigerator body comprises a first inner container and a second inner container positioned in an internal space of the first inner container, an air channel is formed between the first inner container and the second inner container, an air inlet and an air outlet are formed in the second inner container and communicated with the air channel and an internal space of the second inner container, and a fan and an evaporator are mounted between the air inlet and the air outlet in the air channel. Under the action of the fan, air in the internal space of the second inner container forms airflow entering the air channel from the air inlet, the airflow flows out of the air outlet to the internal space of the second inner container after exchanging heat with the evaporator in the air channel, circulation is formed, and the internal space of the second inner container is refrigerated. The refrigerator is high in cooling speed and good in temperature uniformity and can achieve a frostless function, the first inner container and the second inner container of the refrigerator are simply assembled, and procedures, mounting time and manpower are greatly saved.