Structure, morphology, and magnetic properties of perovskite La0.7Sr0.2Ba0.1Mn1-xCrxO3 (x = 0; 0.03; 0.05; 0.07 and 0.1) synthesized via sol-gel method have been studied. X-ray diffraction studies confirm the Rhombohedral structure with R-3c space groups for all samples. The magnetization measurements clearly show that magnetization decreases with increasing Cr substitution concentration. The partial substitution of Cr3+ in the Mn site weakens the ferromagnetic double exchange interaction of the Mn3+–O–Mn4+ bond. It is caused by the emergence of the Cr3+–O–Cr3+ antiferromagnetic interaction. As known, the structural parameters affect the magnetic properties of perovskite manganese materials in the double exchange interaction. As the Cr3+ concentration increases, the average Mn-O bond length also increases, and the average Mn-O-Mn bond angle decreases, which dramatically weakens the Mn3+–O–Mn4+ double exchange interaction.