The invention discloses a drilling and charging device used for tunnel blasting excavation and a charging operation method. The device comprises a charging mechanical arm, a drilling mechanical arm, adata collecting instrument I, a data collecting instrument II, a central control computer and an explosive tank, all of which are installed on a vehicle body capable of moving forwards. The drillingmechanical arm is provided with a drill rod sensor. Guide pipes capable of being inserted into blast holes are arranged on the charging mechanical arm. The guide pipes are provided with flow sensors,a pressurizing device is arranged in the explosive tank, and the guide pipe on the charging mechanical arm is connected with the explosive tank through a soft pipe. The method includes the steps thatthe blast holes are drilled in the section of a tunnel through the drilling mechanical arm; the central control computer automatically calculates the rock index the explosive amount needed by loadingthe rock volume of each blast hole and the explosive charging amount of each blast hole, and the hydraulic charging arm is used for inserting the guide pipes into the drilled blast holes, and the calculated amounts of explosives are injected into the holes. Integration, automation and intelligence can be achieved on tunnel drilling and charging, and the blasting effect and the construction efficiency are improved.