In 1941, when the Great Patriotic War broke out he joined the field Forces. After graduation from the accelerated courses of Kharkov Commissariat Academy, Levan Maruashvili took part in the battle by the town of Stalingrad defending the ways leading to the Caucasus. In 1943-1946 he was in "Stepsgeo" team fighting in high-mountains of the Caucasus and participated in the military-geographical expeditions in South Georgia. Being demobilized from the army in 1946, in a very short time he got ready his dissertation - "Karst of fragmental rock, its geomorphological characteristics in the light of general karstology, Central Megrelia as an example (Western Georgia)" and successfully defended his master's degree in 1947.