The invention discloses a low-temperature condensation prevention control air system, comprising an air source (1) used for supplying air for a control air ring pipe (6) through an air pipeline (5); the control air ring pipe (6) is connected with user sides (14) by branch pipelines; the air pipeline (5) is provided with an air dryer (3); an automatic release valve (12) is connected with a position (11) at the lowest point of the control air ring pipe (6); the control air ring pipe (6) is also connected with a dew-point instrument (7) by a branch pipe; the dew-point instrument (7) is connected with a monitoring system (10); the monitoring system (10) is also connected with a temperature sensor (9) which is installed outside a room; the monitoring system (10) is used for comparing the temperature of the dew-point instrument (7) and the temperature of the temperature sensor (9), and controlling the start and stop of the air dryer (3) by means of connection. The low-temperature condensation prevention control air system realizes double insurance of low temperature and condensation prevention, and can effectively guarantee the safety and reliability of the control air system.