Emerging 2D magnetic heterojunctions attract substantial interest due to their potential applications in spintronics. Achieving magnetic phase engineering with structural integrity in 2D heterojunctions is of paramount importance for their magnetism manipulation. Herein, starting with chromium ditelluride (CrTe) as the backbone framework, various lateral and vertical magnetic heterojunctions are obtained via self-intercalated 2D chromium telluride (CrTe). A CrTe-CrTe lateral heterojunction prototype is demonstrated for the manipulation of magnetic moments under different magnitudes of magnetic excitation, showing a sharply stepped hysteresis loop with a dual spin-flip transition at high Curie temperatures up to 150 and 210 K by magneto-optical Kerr measurement. High-resolution scanning transmission electron microscopy and first-principles calculations reveal a preferred random location of Cr intercalants at the phase boundary, allowing lowering energy associated with crystal field splitting. The overall structural rigidity of chromium-telluride heterostructure with magnetic phase decoupled behaviors is promising for 2D spintronic devices.