He studied theology at the Universities of Bonn and Berlin, afterwards serving as an assistant pastor in Koblenz (1849), then as a pastor in Trier (1850).
Beyschlag was the leader of the Evangelical Mittelpartei ("Middle Party"), and in 1876, with Albrecht Wolters, founded the Deutsch-evangelischen Blätter (a publication of the Mittelpartei in the Kirche der Altpreußischen Union).