The invention relates to a delayed cross-linked gel with an interpenetrating network structure and a preparation method thereof. The delayed cross-linked gel is prepared from the following componentsby weight percentage: 0.1-10% of a first thickening agent, 0.1-20% of a second thickening agent, 0.1-1% of a cross-linking agent, 0.05-1% of a pH regulator, 0.01-1% of a bactericide, 0.1-1% of a charge regulator, 10-40% of ethylene glycol and the balance water. The preparation method includes: 1, dissolving the first thickening agent in water, performing mixing, then adding the pH regulator and the bactericide, and mixing the substances uniformly; 2, adding ethylene glycol, the charge regulator and the cross-linking agent into the mixed solution obtained in step 1, and mixing the substances uniformly; after the viscosity of the mixed solution reaches a fixed value, injecting the mixed solution into a petroleum pipeline needing pouring to form a three-dimensional cross-linked network; and 3, pouring a mixture of the second thickening agent, the cross-linking agent and water to two ends of the petroleum pipeline, and letting the gel formed by the second thickening agent permeate into thefirst thickening agent gel system poured into the petroleum pipeline, thus forming the delayed cross-linked gel with an interpenetrating network structure. The gel has good temperature resistance, and can achieve effective plugging of underwater oil and gas pipeline jumper pipes.