The invention discloses a no-cable type submarine observation platform suitable for whole sea depth. The no-cable type submarine observation platform comprises a frame-type body, a floating body, a wing plate, a height measuring device, a floating ball cabin, a leveling mechanism and a counterweight and releasing device, wherein the floating body, the wing plate, the height measuring device, the floating ball cabin, the leveling mechanism and the counterweight and releasing device are mounted on the frame-type body. The floating ball cabin seals a system circuit while providing buoyancy; the system circuit uses the height measuring device to detect that the frame-type body descends to a set height from the seabed, and then controls the wing plate to unfold to enable the platform to land smoothly, and when the frame-type body reaches the seabed, the leveling mechanism is controlled to adjust the frame-type body to stand horizontally on the seabed; and after the underwater operation of the system circuit is completed, the releasing mechanism is controlled to abandon a counterweight and the wing plate is controlled to retract, so that the observation platform emerges from the water under the buoyancy of the floating body, and automatic recovery is realized. The submarine observation platform adopts a no-cable laying method, is not limited by the length of cables, the working waterdepth can reach 11,000 meters or more, and the submarine observation of the whole sea depth can be realized.