Using the full potential linearized augmented plane wave (FLAPW) method, the influences of uniform and tetragonal strains on the magnetic state have been explored for chemically ordered bulk L1₂ FePt₃. The ordered state displays antiferromagnetic Q₁ (AFM-Q₁) state but it transitions into antiferromagnetic Q₂ (AFM-Q₂) state at about 10% uniform strain. The ferromagnetic (FM) state is observed at 11% uniform strain. For tetragonal strain, it is also seen that the transition from AFM-Q₁ to AFM-Q₂ depends on the strength and direction of the applied strain. The FM state does not appear in this case. Magnetocrystalline anisotropy (MCA) calculations for tetragonal distortion reveal that the spin reorientation transition occurs. In addition, we find that the direction of magnetization and the magnitude of magnetic anisotropy energy strongly depend on the c/a ratio.