Sleep apnea is a sleep disorder that can induce hypertension, coronary heart disease, stroke and other diseases, so the detection of sleep apnea is clinically important for the prevention of these diseases. In order to improve the detection performance and verify which physiological signals are better for sleep apnea detection, this paper uses multi-channel signal superposition and channel summation to improve the content of valid information in the original signal. Thirty features are analyzed by Relief feature selection algorithm. Finally, 15 features were used to build a classification model and support vector machine (SVM) was used for classification. The experimental results showed that the highest accuracy of 96.24% was achieved when electrocardiogram (X2) and electroencephalogram (C3-A2) channels were used for channel summation.