ABSTRACT This research work focuses on the theoretical investigation of the upper critical magnetic field, 𝐻𝐶2 for superconductor SrFe2-xCoxAs2. In this research work, we used the Ginzburg-Landau phenomenological theory. From the mathematical computations we performed, the effect of coherence length, penetration depth and anisotropy in mass tensor on upper critical field are considered using the model. Furthermore, the upper critical magnetic field of superconductor SrFe2-xCoxAs2 depends on the angle measured from c-axis, normal to the layers. By using some plausible experimental values in the obtained expressions, phase diagrams of the upper critical magnetic field parallel ( ) // 2 c C H and perpendicular ( ) 2 c C H , to the symmetry axis (𝑐-direction) versus temperature are plotted. From the figure we performed, the critical magnetic fields decay with increasing temperature and reach to zero at the critical temperature, TC and have maximum values at T=0K. We also plotted the phase diagrams of the upper critical magnetic field, 𝐻𝐶2 versus the angle 𝜃. And also we performed the values of the upper critical magnetic field along the 𝑎𝑏- plane ( ) 2 c C H is quite different from the upper critical magnetic field along the 𝑐- axis ( ) // 2 c C H . Similarly, the phase diagrams of the GL coherence length ( ) GL  and GL penetration depth ( ) GL  parallel and perpendicular to the symmetry axis versus temperature are drawn for the superconductor SrFe2-xCoxAs2. The results obtained in this research work are in agreement with experimental observations. Keywords: Superconductor, Ginzburg-Landau equation, critical tempe