To appeal to the dissatisfied, multi-ethnic population of the Soviet Union.
A comment from the History Channel explains the situation in the USSR when Gorbachev was in power. "In 1985, even many of the most conservative hardliners realized that much needed to change. The Soviet economy was faltering and dissidents and internal and external critics were calling for an end to political repression and government secrecy." As far as the aim of Gorbachev's reforms, "The plan was for the Soviet Union to become more transparent, and in turn for the leadership of the nation and the Communist Party to be improved," according to YourDictionary.
In March 1985, Mikhail Gorbachev proposed policies of perestroika (restructuring) and glasnost (openness) in the Soviet Union. These seemed like policies that leaned in the direction of Western ways of economics and politics. Perestroika meant allowing some measure of private enterprise in the Soviet Union. Glasnost meant allowing a bit of freedom in regard to speech and publication. Gorbachev was not trying to get rid of the Soviet communist system. He actually was trying to prop it up and preserve it, because it was starting to have many problems sustaining itself, and there was too much dissatisfaction and dissent occurring among the country's people. But in the end, opening things up a bit with perestroika and glasnost policies pushed the USSR further in the direction of shedding the communist model under which it had lived for so long, and would begin to spell the end of the USSR.