The composite Bi(1-x)SrxFeO3 ( x = 0.0, 0.2, 0.4, 0.6, 0.8 ) was synthesized by solid-state reaction method at 850 °C, in order to evaluate the effect of strontium on the structure. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), magnetic analysis (VSM), and band gap energy measurements were performed by UV- visible spectroscopy. The results obtained are the formation of crystalline materials of rhombohedral surfaces and change to the pseudocubic phase at x = 0.4. The FWHM value ranges from 0.190 to 0.980 and the particle size decreases from 36.5 nm for the pure sample to 17 nm for BSFO. The Sr+2 caused an increase in Remnant magnetization (Mr) and coercive field (Hc), which lead to the magnetization development of BiFeO3, UV- visible spectroscopy used to calculate the direct optical bandgap of all samples had its value on the order of 2.4 to 2.9 eV.