To master the aseismic ability of Shanghai 65m radio telescope structure, according to the information of site conditions, the safety properties of antenna structure in the initial design was analyzed under activities of frequent and rare earthquake by using time-history method when aseismic fortification intensity is Ⅶ. Subsequently mechanical responsive targets which are crucial to the structure under activities of frequent earthquake, frequent earthquake combined with static unitized load mode and infrequent earthquake were given. The results show that the weaknesses of the structure (plastic deform appears in some bars) are found under activities of frequent earthquake combined with static unitized load mode. Under activities of infrequent earthquake, artificial ground motion produces the most intensive effect on the structure. To every kind of different pitching angle model the antenna structure does not break down under the activities of 3 kinds of infrequent earthquake. After some modifications to the initial design, and choosing the most disadvantageous model(its pitching angle is 5°), the analysis results under activities of frequent earthquake show that all targets of all bars meet the corresponding requirements of specifications when aseismic fortification intensity is Ⅷ.