Based on the traditonal model of rational expectation commodity reserve and with the threshold error correction model the paper introduces the adaptive expectation into the commodity supply model and examines the regulatory mechanism and effects of the national meat reserve policy on the fluctuation of hog price under two expectations.The results show that the expectation formation of market players will not only affect the effect of the reserve meat policy, but will also change its operation mode . The reserve meat policy acts on price adjustments under rational expectations in the form of "spot shock" while under adaptive expectations, in the form of “lagged shocks”. Meanwhile,the buffer reserve meat policy with the hog-grain ratio as the starting signal acts as a “reservoir” in stabilizing the fluctuation of hog prices. When the hog-grain ratio is higher than 8.25 or lower than 5.64, the government's reserve throughput makes hog prices rise and fall much faster.Moreover, the regulatory effect of the collection-storage policy is better than that of the release-storage policy, causing asymmetry in the rebounding rate when the price rises or falls ,producing the phenomenon of “easy to rise and difficult to fall”. Whether with the collection-storage policy or with the release-storage policy, the effect of price control under rational expectations is better than adaptive expectations.