The invention discloses a wash basin with good sealing performance and a mounting method of a wash basin main body, and comprises the wash basin with good sealing performance and a mounting method ofthe wash basin with good sealing performance. The wash basin with the good sealing performance comprises a wash basin main body, and a bearing frame horizontally extending to the outside at the upperopening edge of the wash basin main body, and further comprises a sealing gasket, wherein the sealing gasket comprises a cuboid cushion block, a first spring, a first sliding block, a second sliding block, a sliding rod, and a sealing part; a first mounting cavity and a second mounting cavity are respectively on two sides, in contact with the wash basin main body side and the mounting hole side, of the cuboid cushion block; the first mounting side is arranged at one side close to the wash basin main body, and the side directly facing the wash basin main body is opened. The wash basin disclosedby the invention is good in sealing performance and more beautiful, and the wash basin made of aluminum alloy or magnesium alloy is lighter in mass.