The invention discloses a method for collecting high reliability analog quantity of relay protection device. An independent ADC chip is used to monitor an analog power supply of the data ADC chip, andthe CPU periodically reads the voltage value of the analog power supply. When the voltage value exceeds the normal operating range allowed by the data ADC chip, the abnormal alarm of the analog powersupply is generated. When the analog power supply is abnormal, the protection logic locks the trip output, and the merging unit locks the SV message output. When the analog supply voltage returns tonormal operation, the protection logic and merge unit exit the latched state. The analog power supply voltage is confirmed after multiple sampling to prevent the misjudgment caused by instantaneous interference. The invention effectively prevents the wrong data output caused by the abnormal analog power supply of the ADC chip, improves the reliability of the analog quantity collection, and prevents the malfunction of the relay protection device by blocking the local protection trip output and the SV message output.