This　study　aims　to　investigate　the　tensile　failure　behaviours　and　corresponding　fracture　mechanisms　of　basalt　fiber　reinforced　lightweight-aggregate　concrete　(BFLAC)　at　various　temperatures　via　a　comprehensive　cryogenic　tests　and　mesoscale　simulations,　with　a　special　focus　on　the　quantitative　effects　of　cryogenic　temperature　and　fiber　volume　fraction.　Firstly,　Macro-　and　micro-scale　split-tensile　tests　of　BFLAC　with　fiber　volume　fractions　of　0.0-0.3　%　at　20　similar　to-90　degree　celsius　were　conducted.　Secondly,　a　two-steps　sequentially　thermo-mechanical　coupled　mesoscale　analysis　approach　with　explicit　modelling　of　fibers　and　pore　ice　was　developed　to　simulate　the　corresponding　direct-tensile　failures　of　BFLAC　with　more　fiber　volume　fractions.　The　results　show　that　as　the　temperature　falls　from　20　degree　celsius　to　-90　degree　celsius,　the　dominant　action　mechanism　of　basalt　fibers　changes　from　Mode-1　(pullout　of　fibers)　to　Mode-2　(rupture　of　fibers)　due　to　the　ice　formation　and　the　interactions　between　mesocomponents.　Tensile　strengths　of　BFLAC　present　a　significant　low-temperature　enhancing　effect,　with　a　maximum　increase　of　90　%　for　direct-tensile　strength　while　104　%　for　split-tensile　strength.　Besides,　as　the　temperature　drops,　although　a　larger　proportion　of　fibers　are　in　a　low　bridging　stress　state　and　a　smaller　proportion　reach　yield　stress　for　rupture,　the　average　fiber　stress　increases　and　the　utilization　degree　of　fibers　with　more　stresses　transferred　improves,　which　results　in　that　the　fiber　reinforcement　effect　is　strengthened.　Finally,　based　on　experimental　and　numerical　results,　the　quantitative　relationships　between　split-tensile　and　directtensile　strengths　at　different　cryogenic　temperatures　were　given.　The　present　research　results　can　better　understand　the　cryogenic　mechanical　properties　of　BFLAC,　which　have　important　reference　value　for　its　extensive　promotions　and　applications　in　engineering　structures　exposed　to　extreme　low-temperature　environments.