Tanks are structures for storing fluids that are made in different sizes, shapes and genera. Today using of tanks for water, petroleum products storage, and industrial wastes, has been developed significantly. The buried rectangular concrete tanks are used for water supply in most cities in our country. Soil-structure interaction is one of the most important issues in seismic behavior of buried tanks. With respects to code 123 that has suggested Mononobe-Okabe equation for dynamic pressure of earthquake excitation, the purpose of this research is to achieve the dynamic pressure of soil during earthquake. The obtained results have been compared to analytical and other experimental researches. Therefore, a series of small-scale experimental tests were conducted using 1g shaking table testing in the laboratory of physical modeling at University of Tehran. The results illustrate that dynamic force and pressure from Mononobe-Okabe and Wood equation are greater than experimental testing results. However Seed-Whitman equation is closer to experimental results.