The invention discloses a battery overcharge early warning method and system based on big data. The method comprises the steps of: determining the type of a battery; if the battery is a ternary lithium battery, calculating the battery charge state value of the ternary lithium battery; determining whether a fault occurs or not based on the state value; extracting the highest monomer voltage and thehighest probe temperature of the ternary lithium battery; determining the overcharge threshold value of the ternary lithium battery; and classifying fault levels and performing early warning on the basis of the overcharge threshold value, the highest monomer voltage and the highest probe temperature, and if the lithium iron phosphate battery is a lithium iron phosphate battery, classifying the faults of the lithium iron phosphate battery by adopting the same method. According to the method and the system, the overcharge of the battery is graded and early warned, so that the occurrence of safety accidents is reduced.