The medical needle electrode is mainly used by medical practitioners to collect bioelectric signals (EEG, ECG and EMG) from corresponding parts of human bodies during clinical diagnosis, examination, treatment and surgical operations and transmit such signals to nerve monitors, electroencephalograph (EEG), electrocardiograph (ECG), electromyography (EMG) for processing, analysis and diagnosis. Also the subdermal needle electrodes can be used to transmit low-frequency pulse wave sent by the low-frequency therapeutic apparatus to the subcutaneous tissues of patients so as to stimulate peripheral nerves, activate and pace potentials of palsied peripheral nerves of patients.