The　requirement　of　integration　and　heat　dissipation　of　communication　equipment　and　reserve　battery　in　agricultural　base　station　is　getting　higher　and　higher.　High　temperature　affects　the　stability　of　server　equipment　operation　which　reduces　the　comprehensive　performance　and　service　life　of　the　equipment.　In　order　to　solve　this　problem,　air　conditioners　with　enough　redundancy　need　to　operate　continuously　to　ensure　the　normal　operation　of　equipment.　In　order　to　maximize　the　use　of　natural　cold　energy　to　reduce　the　huge　energy　consumption　of　air　conditioners　in　winter　and　transition　season,　this　research　proposed　a　new　type　outdoor　natural　cooling　air　cooler　(NCAC),which　is　composed　of　micro　heat　pipe　array　(MHPA)　with　serrated　fins.　The　serrated　fins　are　used　to　increase　the　air　convective　heat　transfer　area,　and　to　enhance　air　disturbance　and　heat　transfer.　The　parallel　flow　tube　with　tiny　porous　channel　(PFT)　is　used　to　increase　the　water　heat　transfer　area　and　contact　area　to　reduce　the　thermal　resistance.　Under　different　outdoor　environment　temperature,the　performance　of　NCAC　under　different　flow　processes　(downstream　and　countercurrent),　inlet　temperature,　water　flow　rate　and　air　flow　rate　were　separately　investigated,　the　heat　transfer　performance,　temperature　distribution,　exergy　efficiency　and　resistance　characteristics　were　also　analyzed.　Results　showed　that　there　was　little　heat　loss　between　air　and　water　side　of　NCAC,　the　heat　loss　rate　was　under　11%.　The　heat　transfer　performance　of　NCAC　of　countercurrent　process　was　better　than　that　of　downstream　process,　the　maximum　heat　exchange　rate　was　7.5　kW　of　countercurrent　process,　which　is　increased　by　16.9%　than　that　of　the　downstream　process.　For　the　NCAC　of　countercurrent　process,　the　temperature　distribution　uniformity　of　the　micro　heat　pipe　array　was　better,　and　the　maximum　vertical　temperature　difference　in　the　condensation　section　of　the　heat　pipe　was　1.03.　The　temperature　difference　between　the　evaporation　section　and　the　condensation　section　was　6.96,　the　equivalent　thermal　conductivity　reached　to　1.72×104　W/(m•K).　The　pressure　drop　of　the　air　side　and　water　was　at　a　low　level,　the　maximum　resistance　of　the　air　was　345.5　Pa,　and　the　maximum　resistance　of　the　water　was　8.92　kPa.　The　highest　exergy　efficiency　researched　38.8%,　the　heat　transfer　capacity　of　NCAC　still　has　large　space　for　improvement.　The　average　energy　efficiency　factor　was　over　17.2,　the　air　cooler　was　in　a　better　operation　state.　The　experimental　values　of　heat　transfer　factor　and　friction　factor　were　obtained　according　to　the　test　of　NCAC　with　serrated　fins,　the　average　value　of　comprehensive　evaluation　index　was　about　0.049,　which　increased　by　36.1%　compared　to　the　plate　fin　heat　exchanger　with　plain　fins.　The　experimental　results　show　that　with　the　increase　of　air　flow,　the　increase　of　pressure　drop　is　greater　than　the　increase　of　heat　transfer　rate,　and　various　factors　must　be　considered　comprehensively　in　the　process　of　heat　transfer　enhancement.　The　research　results　can　provide　reference　for　design　calculation,　model　simulation　and　practical　application　of　air　cooler　used　in　base　station.　©　2020,　Editorial　Department　of　the　Transactions　of　the　Chinese　Society　of　Agricultural　Engineering.　All　right　reserved.