A tank cover, a liquid storage tank, and an unmanned aerial vehicle. A tank cover (30) comprises: a hoop (1) fixedly connected to a liquid storage tank; a cover body (2) fitting the hoop, the cover body and the hoop forming an accommodating space (3), the cover body being provided with an opening (21), and the opening being communicated with the accommodating space; and a sealing structure (4) accommodated in the accommodating space and rotationally connected to the cover body, the sealing structure comprising a sealed state and an open state, wherein when the sealing structure is in the sealed state, the sealing structure fits the opening under the effect of a locking force of the sealing structure to seal the opening, and when a pressure is applied to the sealing structure, the sealing structure can rotate with respect to the cover body in the accommodating space to be in the open state to open the opening. A sealing structure that can rotate with respect to the cover body is provided on the cover body, and under the effect of an external pressure, the sealing structure can overcome its locking force and rotate with respect to the cover body to be in the open state to open the opening, without manually opening the tank cover.La présente invention concerne un couvercle de réservoir, un réservoir de stockage de liquide et un véhicule aérien sans pilote. Un couvercle de réservoir (30) comprend : un cerceau (1) relié de manière fixe à un réservoir de stockage de liquide ; un corps de couvercle (2) ajustant le cerceau, le corps de couvercle et le cerceau formant un espace de réception (3), le corps de couvercle étant pourvu d'une ouverture (21), et l'ouverture étant en communication avec l'espace de réception ; et une structure d'étanchéité (4) logée dans l'espace de réception et reliée en rotation au corps de couvercle, la structure d'étanchéité comprenant un état fermé et un état ouvert, lorsque la structure d'étanchéité est en état fermé, la structure d'étanchéité s