As one of the core equipment of floating liquid natural gas (FLNG), the spiral wound heat exchanger (SWHE) will be affected by feed gas flow and sea conditions, which will lead to more complex flow and heat transfer process inside the heat exchanger. In this paper, the experimental device of SWHE based on dual mixed refrigeration (DMR) liquefaction process is built to test the adaptability of feed gas flow and sea conditions on SWHE. Meanwhile, a multi-phase four-stream code for liquid natural gas (LNG) SWHE is developed. The following conclusions are obtained: (1) the parallel heat transfer calculation program can predict the change of the heat transfer coefficient and the temperature inside the heat exchanger well. (2) The temperature decreasing rate of feed gas inside SWHE decreases gradually. When the feed gas is liquefied completely, the temperature decreasing rate increases gradually. (3) The heat transfer performance of SWHE is greatly affected under sea conditions. (C) 2019 Elsevier Ltd. All rights reserved.