The invention discloses a dimming circuit compatible with a silicon controlled rectifier dimmer and a control method. The dimming circuit includes an input voltage source, a rectification circuit, the silicon controlled rectifier dimmer, a dimming circuit and an output circuit, wherein the input voltage source is connected with the rectification circuit and the silicon controlled rectifier dimmer respectively, the rectification circuit is connected with the dimming circuit, the dimming circuit is connected with the output circuit, and the output circuit includes an isolation transformer, a switch tube, a third sampling resistor, a flyback diode, a filtering capacitor and an output LED load. The dimming circuit compatible with the silicon controlled rectifier dimmer is characterized in that the dimming circuit includes a sampling circuit used for sampling the phase-cut angle of the silicon controlled rectifier dimmer, a control and logic circuit which is controlled by the phase-cut angle, and a phase-cut angle setting circuit which can control the switching on and switching off of the switch tube according to the status of an inputted phase-cut angle. With the dimming circuit compatible with the silicon controlled rectifier dimmer of the invention adopted, the problem of flicker appearing in a traditional dimming process can be effectively solved, and at the same time, a dimming purpose can be achieved.