A boat that is provided with floating tubes in a multi-layer design is composed a plurality of floating tube devices which are installed respectively at a left and a right side of a hull, and is provided with an air bag, a buffer, and a surface layer unit. The buffer is provided with a holding space and an assembling slot hole; whereas, the surface layer unit is provided with a sealing element which is used to seal the assembling slot hole, such that the floating tube devices are configured as a multi-layer design to facilitate balance, anti-collision, and increase of chance of survival.