A monolayer of CrI3 is a two-dimensional crystal in its equilibrium configuration is a ferromagnetic semiconductor. In contrast, two coupled layers can be ferromagnetic, or antiferromagnetic depending on the stacking. We study the magnetic phase diagram upon the strain of the antiferromagnetically coupled bilayer with C2/m symmetry. We found that strain can be an efficient tool to tune the magnetic phase of the structure. A tensile strain stabilizes the antiferromagnetic phase, while a compressive strain turns the system ferromagnetic. We associate that behavior to the relative displacement between layers induced by the strain. We also study the evolution of the magnetic anisotropy, the magnetic exchange coupling, and how the Curie temperature is affected by the strain.