The invention provides a sliding rail type hermetically sealed lithium battery power system. The sliding rail type hermetically sealed lithium battery power system comprises a box body and a sliding rail frame which are mounted in a mutually cooperating way, wherein a plurality of battery modules are arranged in the box body, each battery module comprises an integrated mold and a battery cell arranged on the integrated mold, a bus board is arranged on the integrated mold, a box cover and a high-low pressure connector which are matched with the box body are arranged on the box body respectively, an insulating plate is arranged between the battery modules and the box cover, and a waterproof adhesive tape is arranged on the high-low pressure connector. The sliding rail type hermetically sealed lithium battery power system is low in cost, high in structural strength, good in waterproof performance and easy to mount, and a box can be conveniently changed.