Objective　To study clinical characteristics, diagnosis and treatment of childhood hypokalaemic periodic paralysis. Methods　The clinical data from two cases of childhood hypokalaemic periodic paralysis admitted from August 2014 to October 2014 were retrospectively analyzed. Results　Both patients had the limb weakness at dawn as the onset symptom. The limb weakness was recurrent and got worse progressively, and each attack lasted approximately 2-24 hours. The serum potassium was low during the attack and the serum potassium was normal during the intermission. CACNA1S gene mutation was detected in both patients and their family members. Oral administration of potassium was effective to relieve the symptom. Conclusions For the children with recurrent limb weakness, great attention should be paid to the possibility of hypokalemic periodic paralysis. Genetic tests may be helpful for the diagnosis and treatment.