The invention relates to a charging current detection circuit, which is technically characterized in that an IP- pin of a current detection chip ACS712 is connected with the positive electrode of a lithium battery; an IP+ pin is connected with the positive electrode P+ of a battery system; a pin of a filter is connected with a noise reduction capacitor C2; a VIOUT pin is connected with an AD end of a controller; a Vcc pin is connected with a power supply +5V and a decoupling capacitor C1; the other end of the decoupling capacitor C1 is grounded; an over discharge control end DCH of the controller is connected with a gate of an over discharge control tube; an overcharge control end CH of the controller is connected with a gate of an overcharge control tube; the negative electrode of the lithium battery is connected with the source of the over discharge control tube and grounded; a drain of the over discharge control tube is connected with a drain of the overcharge control tube; and the source of the overcharge control tube is connected with the negative electrode P- of the battery system. Charge and discharge current as high as tens of amperes can be detected at an extremely low cost, and the problems that the charging current detection circuit is high in cost and the detection current is small in the existing lithium battery protection circuit can be solved.