The invention aims at providing a combined dual pressurizing electromagnetic fuel oil injection and piezoelectric fuel gas injection mixed fuel injection device.The device comprises a pressurizing part, an electromagnetic and piezoelectric control part, a nozzle part, a fuel gas inlet channel, a fuel oil inlet channel, an oil leakage channel and the like.A pressurizing electromagnetic valve is used for controlling motion of a pressurizing piston to achieve pressurizing of fuel gas and fuel oil, the fuel gas and fuel oil pressurizing timing is controllable, switching of fuel pressurizing injection and fuel non-pressurizing injection can be achieved rapidly, and the different requirements of different powers of a dual-fuel engine on fuel gas and fuel oil injection pressure are met; by controlling the working states and working sequence of the pressurizing electromagnetic valve, a fuel oil electromagnetic valve and a piezoelectric element, the mixed fuel injection device can achieve four injection modes of non-pressurized fuel oil injection, pressurized fuel oil injection, non-pressurized fuel oil and non-pressurized fuel gas dual-fuel injection and pressurized fuel oil and pressurized fuel gas dual-fuel injection.