The invention discloses a lava drilling device. The lava drilling device comprises a main rod body made of a high-temperature-resistant material, a focusing device, a high-pressure air pipe, a safetyprotection baffle and a handle, wherein a laser/sunlight channel is formed in the main rod body; a laser emitter or a solar energy collector is mounted at an inlet of the laser/sunlight channel; the focusing device is mounted on the main rod body at an outlet of the laser/sunlight channel; a drilling bit of the drilling device is formed in an energy output end of the focusing device; the high-pressure air pipe is arranged in the main rod body; an outlet of the high-pressure air pipe is located in the drilling bit; the safety protection baffle and the handle used for operating are arranged at the other end of the main rod body; meanwhile, high-pressure air blown in the high-pressure air pipe is used for blowing molten rock away to form holes. The invention also discloses a tunnel construction method based on a lava technology. The lava drilling device and the tunnel construction method based on the lava technology have the beneficial effects that the solar energy or the laser is used for melting and drilling the rock, the high-pressure air is used for blowing the rock away so as to achieve the purpose of cutting, the construction method is green and environmentally friendly, and theengineering cost is reduced.