Abstract In this work theoretical investigation of upper critical magnetic eld in superconductor CeO 1x F x BiS has been made. This compound was found to undergo a transition from the normal state to the superconducting state at T 2 =3 K and returned to a normal state if external magnetic eld is not applied. But it can be changed to normal state even at absolute zero when high magnetic eld is applied. By using the Ginzburg-Landau (GL) phenomenological equation, we obtain expressions for the upper critical magnetic eld (H c2 c ), the GL coherence length ( ) and GL penetration depth ( GL ) for CeO 1x F x BiS 2 GL superconductor. The upper critical magnetic eld versus temperature, the GL coherence length versus temperature and GL penetration depth versus temperature phase diagrams are drawn using some plausible experimental and theoretical values of the parameters in the obtained expressions. The phase diagrams show the invers linear dependence of upper critical magnetic eld (H ) on temperature (T) and increment of both GL coherence length ( GL c2 ) and GL penetration depth ( ) with temperature (T). Our ndings are in agreement with experimental observations. GL Key words: Ginzburg-Landau Equation, Upper Critical Magnetic Field, GL coherence length, GL penetration depth, CeO 1x F x BiS 2