The invention provides an integrated modular oil tank. The integrated modular oil tank comprises a plurality of oil tank bodies, oil and gas separation devices, defoaming plates and a modular base; the plurality of oil tank bodies are arranged on the modular base; every oil and gas separation device and the corresponding defoaming plate are arranged in the corresponding oil tank body; an oil inlet pipeline and an oil outlet pipeline are arranged in the modular base; the oil enters every oil tank body through the oil inlet pipeline and the oil outlet pipeline in turn. According to the integrated modular oil tank, the oil is in and out from the bottom of the oil tank, the oil and gas separation devices, the number adjustable defoaming plates and other structures are combined, and accordingly the separation efficiency of the oil and gas mixture aerosol is improved, the defoaming space required by the oil tank is reduced, and the oil emission of a breathing device of an engine is improved so as to ensure the safety of the use of parts arranged in a power cabin and extend the service life of the parts and different sizes and shapes of oil tanks are assembled through the modular base so as to meet the use requirements of the space optimization of the power cabin.