On June 22, 1941, Hitler ordered the German army to implement the "Barbarossa" plan, and the German army launched a lightning surprise attack on the Soviet Union with 146 divisions, 3,580 tanks, and 4,980 aircraft, and the Soviet-German war broke out. The invading German army was divided into 3 army groups: Army Group North 26 divisions, commanded by Field Marshal Loeb, set out from East Prussia and crossed the three Baltic countries, aiming at Leningrad; The 49 divisions of Army Group Center, commanded by Field Marshal von Bock, attacked from the Warsaw area, passing through Brest-Minsk-Smolensk, and taking Moscow; Army Group South 39 divisions were commanded by Marshal Rundstedt and aimed at Kiev.

The Barbarossa plan was to concentrate a large number of troops, carry out a rapid and far-reaching assault from several directions with a "blitzkrieg", occupy Moscow (Москва), Leningrad (Ленинград) and Kiev (Київ, Киев), etc., and wipe out the main forces of the Soviet Red Army in the western regions of the Soviet Union, and then drive straight into the hinterland of the Soviet Union, reaching Arkhangelsk (Архангельск), the Volga River (Волга), Astrakhan (Астрахань) on the front line and the destruction of the Ural industrial region with the Air Force, thereby defeating the USSR.

On May 1, 1941, a military parade was held on Red Square in Moscow to commemorate International Labor Day, although Britain and other countries and Soviet spies repeatedly reported to Stalin that Germany would attack the Soviet Union in the summer of 1941, Stalin believed that Germany was not capable of attacking the Soviet Union before the war between Britain and Germany was clear. He even suspected that it was fabricated by British spies in order to draw the Soviet Union into the trap of war against Germany.

After the start of Operation Barbarossa, the Wehrmacht achieved great success on the northern and central fronts, leaving only a huge salient in the south, where there was a large Red Army, including almost the entire Southwestern Front, and although it achieved a great victory in the Battle of Uman, most of the Red Army remained in the area of Kiev under the command of Semyon Budyonny, and since most of the armored forces had been destroyed in the Battle of Uman, they lacked armor and mobile forces. They could no longer threaten the German offensive and were at that time the largest force of the Red Army on the Eastern Front.

At the end of August 1941, the High Command of the Wehrmacht was faced with the choice of continuing the offensive on Moscow or destroying the Soviet Red Army in the south. Budyonny was caught off guard by the rapid attack of the armored forces to complete the encirclement, and he was removed from his post as commander of the Southwestern Front by Stalin on 13 September 1941. At 6:20 p.m. on September 16, 1941, the advance forces of Paul Ludwig Ewald von Kleist's 1st Panzer Group and Heinz Guderian's 2nd Panzer Group met at Lokhvica, 200 km east of Kiev, to complete the encirclement. According to the statistics of the command of the Southwestern Front, a total of 532,000 Soviet Red Army soldiers were surrounded.

The Soviet Red Army participated in the battle with the Southwestern Front (commanded by General Kirponos), the Bryansk Front (commanded by Lieutenant General Yeremenko) and the Southern Front (commanded by General Tyulenev), and the German troops participating in the battle included Army Group "South" (commanded by Marshal Rundstedt) and Army Group "Center" (commanded by Field Marshal Bock)

The Barbarossa plan planned by the German Führer Hitler had been formulated, but Stalin still did not believe in these things, believing that Hitler did not have the spare forces to wage war, and the German and Soviet armies on the Eastern Front had exchanged fire, and the small Soviet Union would attack the Nazis。。。。。。。。