The invention discloses a boiler-front feeding device of a biomass boiler, comprising a motor and a speed reducer, rotating shaft, helical blades and feeding pipes, wherein the speed reducer is connected with the motor, and the motor and the speed reducer are arranged outside the boiler; one end of the rotating shaft is connected with the speed reducer, and the other end thereof extends to the inside of the boiler; the helical blades are fixedly sleeved on the rotating shaft, and the diameter and the screw pitch of the a discharging end of each helical blade is bigger than that of the feeding end of each helical blade; and the feeding pipes are sleeved outside the helical blades and provided with feed ports. A gearing pedestal is arranged between a helical transporter and the motor, thus ensuring the axiality of a shaft, preventing the movement of the shaft, improving the anti-torque and anti-bending properties of the shaft, avoiding the curve of the shaft and the bucking of the blades and prolonging the service life of the shaft. In addition, as the diameter and the screw pitch of the discharging end of each helical blade is bigger than that of the feeding end of each helical blade, the transporting amount of the biomass particles at the discharging end is larger than that of the feeding end, thereby effectively preventing blocking of the biomass particles at the discharging end and ensuring safe, rapid and even transportation of the biomass particles.