How did Reconstruction affect the lives of African Americans?
Any benefit that African Americans received from Reconstruction is problematic at best, and most historians will argue that Reconstruction was a failure. African Americans were freed by the Thirteenth Amendment, but gained little thereafter. The defeated Southern States were bitter and resentful, and determined to keep African Americans as near slavery as possible. Most Southern States passed "Black Codes that severely restricted the rights of African Americans. Although they were guaranteed civil rights under the Fourteenth Amendment, their rights were violated with abandon. Blacks were forced to use separate facilities and denied the right to sit on juries. In fact, in 1896, the U.S. Supreme Court sanctioned the actions of Southern States in the case of Plessy vs.Ferguson in which the Court held that racially separated facilities were constitutionally protected, as long as they were "equal;" hence the doctrine of "Separate but Equal" which remained in force until 1954. Similarly, African Americans were guaranteed the right to vote under the Fifteenth Amendment; yet Southern States developed creative ways to circumvent this Amendment, typically by imposing poll taxes, literacy requirements, etc. The Freedman's Bureau and other organizations attempted to help blacks; however their efforts were often frustrated by groups such as the Ku Klux Klan and Knights of the White Camellia which terrorized African Americans. Ultimately, those who came to help withdrew. When Reconstruction ended with a political deal to ensure the election of Rutherford B. Hayes to the White House, Southern Blacks had made little progress, other than their freedom.
This is a complicated question because there are many ways to read it. For example, are you asking how African Americans lived during Reconstruction or are you asking how Reconstruction affected their lives after it was over?
During Reconstruction, African Americans were better off than they had been before (obviously) and better off than they would be in the years following Reconstruction. So you can say that Reconstruction improved their lives while it was happening but did not do much to help them in the long run.
While Reconstruction was happening, blacks had political rights and some amount of social services provided by the Freedmen's Bureau. They were encouraged by the bureau to set up various sorts of self-help societies and to create black schools and churches. These sorts of efforts improved their communities and the political rights gave them some power.
After Reconstruction ended, however, the political rights and social services disappeared. Blacks were left to fend for themselves economically and socially. Their right to vote was taken away.
So Reconstruction was (relatively) good from blacks while it lasted but it did not create any lasting benefits.