Abstract: Food security concerns national economy and people's livelihood. Underground silo plays an important role in guaranteeing the safety of grain quality, and is also an important technical support for building a green and ecological grain storage system. The underground silo is an important technical development for building a new system of green grain storage. Compared with the overground silo, the underground silo makes full use of the underground space, which shows significant advantages such as low temperature, loss reduction, eco-friendly environment, land saving, energy saving and safety in grain storage. Currently, such technology has become one of the important research interests in the food industry. In this study, a new type of underground silo consisting of precast steel plate-concrete composite walls was proposed. For the steel plate-concrete composite silo wall (thin column shell) composed of steel plate and concrete, the elastic stress of the composite silo wall was studied under the action of uniformly distributed external pressure. According to the theory of elastic mechanics, the stress boundary condition, interface condition and displacement single value condition of the calculation model were established, and then the stress calculation formula of the double-layer cylindrical shell subjected to uniform external pressure was derived.Taking the structural parameters of the steel-concrete composite silo wall as an example, the calculation results of the example were obtained by using the stress calculation formula derived in this study, and the numerical solutions of the example was obtained by using the finite element method. These results match well, which shows the stress calculation formula is reasonable. The formula for calculating the elastic stress of double layer different material cylinder under uniform external pressure can solve the stress problem of steel-concrete composite wall of underground circular silo, which provides a theoretical reference for the application of steel plate-concrete composite silo wall of the new type underground circular silo and provides a reference for the stress calculation of similar composite structures.