The invention relates to a mechanical hole inserting device for mortar addition cementitious sand gravel vibration and a construction method thereof. The mechanical hole inserting device is characterized by being provided with a power source used for providing vibration force allowing vibration back and forth in the first direction to be achieved, and an insertion head provided with a first end and a second end distributed in the first direction, and the first end is connected to the power source and enables the vibration force generated by the power source to be applied to the insertion head to drive the second end of the insertion head to vibrate back and forth in the first direction. By the adoption of the mechanical hole inserting device, hole forming difficulty can be effectively lowered, pore forming depth meets the mortar addition technical requirement of mortar addition cementitious sand gravel vibration, mortar in a hole can permeate to the bottom and periphery more smoothly, and mortar addition cementitious sand gravel vibration quality can be effectively improved. Preferably, a support is arranged, and the insertion head is connected to the power source through the support so that vibration force provided by the power source can be effectively transmitted to the insertion head.