Outdoor unpowered underwater observation device and observation method thereof

The invention discloses an outdoor unpowered underwater observation device and an observation method thereof.The observation device comprises a lower mirror barrel, the lower end of a barrel body of the lower mirror barrel is open, and the lower mirror barrel submerges and floats below the water surface through a bottom adjustable air cavity; the lower end of the upper mirror barrel penetrates through the overhead plank road paving plane, and the upper mirror barrel and the lower mirror barrel are in sliding connection through a vertical sliding rail pair; the first height lifting adjusting mechanism is used for adjusting the relative height among the upper mirror barrel, the lower mirror barrel and the overhead plank road paving plane; the second height lifting adjusting mechanism is used for adjusting the submerging depth of the lower lens barrel in water; a horizontal rotating mechanism is also arranged between the outer wall of the upper mirror barrel and the paving plane of the overhead plank road; and t