A laser diode chip includes a removable substrate, a first semiconductor layer disposed on the removable substrate, an emitting layer disposed on one part of the first semiconductor layer, a second semiconductor layer disposed on the emitting layer and forming a ridge mesa, a current conducting layer disposed on another part of the first semiconductor layer, a patterned insulating layer covering the second semiconductor layer and the current conducting layer and including a first zone and a second zone which respectively expose a part of the current conducting layer and a part of the second semiconductor layer, a first electrode and a second electrode respectively disposed on the first zone and the second zone. A projection of the ridge mesa projected to the removable substrate covers a part of projections of the first electrode and the second electrode projected to the removable substrate.