Objective To Assess the efficacy of using lung ultrasound to guide alveolar recruitment maneuver in patients with acute respiratory distress syndrome (ARDS). Methods Sixty patients with ARDS were randomly divided into two groups, ie, maximal oxygenation group (n=30) and lung ultrasound group (n=30). All the patients had artificial airway and needed mechanical ventilation. The patients in the two groups accepted recruitment maneuver guided by maximal oxygenation or lung ultrasound respectively. During the course of recruitment maneuver, the arterial partial pressure of oxygen (PaO2), positive end-expiratory pressure (PEEP), central venous pressure (CVP), mean arterial pressure (MAP), cardiac output (CO), and extravascular lung water index (EVLWI) were recorded and compared between both groups. Results The PaO2 in lung ultrasound group was higher than that in maximal oxygenation group (P=0.04). The PEEP was higher in lung ultrasound group but without significant difference (P=0.910). There was no significant difference of the other outcomes (CVP, MAP, CO, EVLWI) between the two groups (all P>0.05). Conclusion Lung ultrasound is an effective means that has good repeatability and security for guiding recruitment maneuver in patients with ARDS.