The shortcomings of laryngeal mask airway (LMA (TM)), such as upper airway obstruction and gastric distension or airway leakage, may limit its application in small children. The I-gel (TM) (I-gel), LMA-Supreme (TM) (LMA-S), and Ambu AuraOnce (TM) (Ambu) are three improvements upon these shortcomings. This study adopted respiratory dynamic monitoring to observe the ventilation parameters of the three laryngeal masks in small children. A total of 105 children were randomized into Ambu (n = 35), I-gel (n = 35), and LMA-S (n = 35) groups. Primary outcomes included leak pressure and respiratory dynamic data. Secondary outcomes included hemodynamic data and bispectral index values after induction (T-0), time after successful laryngeal mask insertion (T-1) and at three recording points every 10 min after insertion (T-2, T-3, and T-4), as well as laryngeal mask related adverse reactions. The inspiratory/expiratory tidal volume per kilogram of body weight in the Ambu group was significantly different from those in the other groups (P < 0.05), while the leak pressure in the Ambu group was significantly lower (P < 0.05). At T-3 and T-4, the expiratory resistance values in the Ambu group were significantly lower than those in the LMA-S group (P < 0.05). We have shown that the three laryngeal masks provided secure ventilation in children < 6 years of age by using continuous respiratory dynamic monitoring. We concluded that the I-gel presented a better sealing effect and fewer adverse reactions.