Considering　the　characteristics　of　concrete　mesocomponents,　a　mesoscale　finite　element　analysis　method　is　proposed　in　this　paper.　The　static　uniaxial　compressive　response　of　geometrically　similar　concrete　cubes　with　different　structural　sizes　at　room　and　cryogenic　temperatures　is　simulated.　The　degradation　behavior　of　nominal　strength　of　concrete　under　uniaxial　compression　at　cryogenic　temperature　and　the　corresponding　size　effect　are　discussed.The　results　showed　that　as　temperature　decreases,　the　uniaxial　nominal　compressive　strength　significantly　increases,　the　brittleness　of　concrete　increases,　and　the　size　effect　becomes　more　obvious.　When　the　temperature　reaches　-120,　the　compressive　strength　and　brittleness　of　concrete　are　the　highest,　exhibiting　the　strongest　size　effect.　As　the　temperature　is　decreased　further,　the　compressive　strength　decreases　slightly　within　a　narrow　range.　The　classical　Type-　2　size　effect　law　can　describe　the　size　effect　results　obtained　using　the　finite　element　analysis　at　different　temperatures.　©　2021,　Science　Press.　All　right　reserved.