The embodiment of the invention provides a construction method for a shallow buried loess tunnel with an underneath passing oil pipeline. The construction method comprises the steps that, a settlementcontrol value of the tunnel is determined; a middle pipe shed and an advanced small pipe are crossly arranged in the vault preset arc length of the tunnel; and the tunnel is excavated according to athree-step reserved core-soil excavating method based on the settlement control value of the tunnel, and while upper steps, middle steps, lower steps, and an inverted arch are excavated, preliminary supporting is carried out on the upper steps, the middle steps, the lower steps, and the inverted arch until excavating of the tunnel is completed. The preliminary supporting comprises the steps that,an arch frame is set up around the arch wall of the tunnel; arch feet of the arch frame are reinforced; a foot-locking anchor pipe is constructed in the arch wall, and the foot-locking anchor pipe andthe arch frame are connected fixedly; and concrete is wetly-sprayed to the arch wall on the back of the arch frame, and a mortar anchor bar is driven to the arch wall. The construction difficulty ofthe tunnel underneath passing oil pipeline is reduced, and construction safety of the tunnel underneath passing oil pipeline is improved.