The invention discloses a light-control digital interface circuit, which belongs to a light control circuit. The light-control digital interface circuit comprises a bridge rectifier D1 and at least two optical coupling units, wherein the bridge rectifier D1 is connected with a bus and is used for outputting or inputting electric level signals via optical couplers in the two optical coupling units; one pin of the bridge rectifier D1 is respectively connected to the optical couplers U1 and U2 in the two optical coupling units via NMOS (N-channel Metal Oxide Semiconductor) transistors Q1 and Q3; the optical coupler U1 is connected to an electrical level receiving end Q2; the NMOS transistor Q1 is also connected with at least two large-value resistors R3 and R4 in series and the NMOS transistor Q3 is also connected with multiple bias resistors in series; the multiple bias resistors and a triode Q4 form a clamping voltage circuit; and the loop of the optical coupler U1 is connected in the other pin of the bridge rectifier D1 via a voltage stabilizing tube D2 and the loop of the optical coupler U2 is also connected to one pin in the bridge rectifier D1, to which the optical coupler U1 is connected, through a capacitor C4. The light-control digital interface circuit has the advantages of simple structure and low power consumption and can be used for receiving and transmitting electrical level signals from the bus accurately and effectively.