The invention relates to a curtain cutting device, which comprises a body component (20) which comprises at least more than one sideboard serving as a fixed bracket, a curtain guide group (22) and an open pore (221) matched with the curtain (60) for the curtain (60) to run through and is fixedly connected on a seat body (21); a cutting component (30) which is arranged above the curtain guide group (22), fixed on the sideboard at one end, at least comprises a driving screw (31) and corresponding first and second crank arm groups (32) and (33) pivoted on two sides of the driving screw (31) respectively and is used for upwards pushing a cutting tool (34) to move up and down; a chucking component (40) which at least comprises a first chucking block (43) and second chucking block (44), whereinthe first chucking block comprises mutually scarfed first and second tracks (41) and (42) for supporting the seat body (21) and is fixed at two ends of the seat body (21), and the second chucking block (44) has a screw rod (441) and can be finely adjusted; and a curtain measuring group (50) which is arranged on the other side of the seat body (21) and comprises a fixed body (51), a block body (52) combined with the fixed body (51) and a mobile block (53) capable of forming a pivot joint with the fixed body (51) and displacing. Therefore, the curtain cutting device can carry out labor-saving cutting operation which can cut off the curtain at one time.