The invention discloses a filter anti-leakage type oil tank of a diesel engine. The filter anti-leakage type oil tank comprises an outer tank body and an inner tank body, wherein a cavity is arranged between the outer tank body and the inner tank body; an oil inlet tube is fixedly arranged on the center of the top end of the outer tank body; a filter device is arranged in the oil inlet tube; the filter device comprises an outer filter screen and an inner filter screen; a filter cavity is arranged between the outer filter screen and the inner filter screen; the portion, positioned at one side of the oil inlet tube, at the top end of the outer tank body is fixedly equipped with a guide-out tube; an oil outlet tube is fixedly arranged at the bottom end of the outer tank body; in a using process, the oil tank performs multi-layer filtration on diesel oil, so that purity of the diesel oil is improved; when oil is added into the oil tank, oil adding is more convenient through a funnel-shaped oil adding hole; the diesel oil also can be prevented from overflowing as a result of too high oil adding speed; the cavity is arranged to effectively prevent damage and oil-leakage phenomenon in the inner tank body; the service life of the diesel engine is prolonged and safety of the diesel engine is improved; and purity of the diesel oil is greatly improved.