The invention discloses a protection method for safe charging of an electric car. The method specifically includes the steps of A, over-current protection, B, over-
voltage and under-
voltage protection, C, over-temperature protection, D, unearthed and live and null wire phase protection and E, earth leakage protection; whether the over-current protection is carried out is determined according to the time of duration of an over-current state; whether the over-
voltage and under-voltage protection is carried out is determined according to the time of duration of an over-voltage or under-voltage state; according to the over-temperature protection, the magnitude of charging current is indirectly adjusted by adjusting communication data with a vehicle through an
alternating current charging device according to the temperature rise state when a power supply end is plugged; according to the unearthed and live and null wire phase protection, after the
alternating current charging device is powered on, whether a power supply wiring state is correct is detected in real time, namely whether earthing is reliable and whether phase
dislocation of a live wire and a null wire of the power supply end occurs are detected, and on-off control over a charging power source is carried out according to actual application requirements; according to the earth leakage protection, after the
alternating current charging device is powered on, the magnitude of leakage current between the live wire and the null wire and a ground wire in the whole alternating current supply process is detected in real time, and when the leakage current exceeds a set threshold value, charging power supply is
cut off. Safe charging is ensured.