The invention discloses a die cutting device applied to mobile phone machining. The die cutting device comprises a lower die base, supporting pillars are arranged at both sides of the upper end of thelower die base, a cross plate is arranged at the upper ends of the supporting pillars, an oil cylinder is fixedly installed at the upper end of the cross plate, the tail end of a piston rod of the oil cylinder penetrates through the cross plate and extends to the lower end of the cross plate, the two supporting pillars are slidably sleeved with an upper die base and penetrate through the two sides of the upper die base respectively, the tail end of the piston rod of the oil cylinder is fixed to the upper end of the upper die base, a fixed plate is fixedly installed at the lower end of the upper die base, a pressing die is fixedly installed at the lower end of the fixed plate, guiding blocks are arranged at the edges of the lower ends of the pressing die, an annular tool is arranged in themiddle of the lower end of the pressing die, exhaust holes and multiple locating blocks are arranged at the lower end of the pressing die, and an air blowing machine is arranged at the upper end of the upper die base. The die cutting device is simple in structure, convenient to operate, and high in locating speed and machining precision; meanwhile, the die cutting device facilitates chip removal,and is suitable for being popularized.