The Soviet Union has a <u>one party system</u>, historically resulting from the working class, much like today China. The Soviets believed multiple parties represented the class struggle, they wanted to see absent in Soviet society, the official name was the Communist Party of the Soviet Union.
There was no official religion, so it was considered an atheist state, secular state. In many of its history it came to prosecute religious practices, in some cases having strong consequences for the Russian Orthodox Church.
The system was designed as communist from Marxist Leninist theories on economy, politics and society. The consecuences of this result in political economy and the way the means of production are held by state intervention.