A power-off delay time relay control circuit comprises a first circuit and a second circuit. The control circuit is characterized in that the first circuit comprises a power source 1, a power source 2, a rectifier bridge stack, a slide resistor, a plurality of diodes, a plurality of capacitors and a resistor RS2. The power source 1 is connected with the pin 1 of the full-bridge rectifier bridge stack. The power source 2, after connecting in series with the slide resistor, is connected with another pin 3 of the rectifier bridge stack. The pin 2 of the rectifier bridge stack is branched into three branches. After the three branches are in parallel connection and are connected with a null line, the three branches are connected with the pin 4 of the rectifier bridge stack to form a loop. The branch 1 is connected in series with a capacitor C1. The branch 2 is connected in series with D1 and the capacitor CR1. The branch 3 is connected in parallel with the capacitor CS1 and the resistor RS2 and then is in series connection with D2. The control circuit is capable of prolonging power supply maintenance time after power off without large-capacity energy storage element, and thus the structure is reduced greatly.