TheJunngar basin has been one of the most important petroliferous basins in western China. The Toutunhe and Qigu formations in the UpperMiddle Jurassic Fudong slope area are the recent key strata for exploration. Based on field outcrop, drilling cores and analysis test data, character differences of reservoirs in the Toutunhe and Qigu formations were studied in detail using petrolgic characteristics and physical properties differences of reservoirs. For the former, comparative study was performed on clastic, interstitial material, pore types and structural characteristics, and for the latter, reservoir type is the focus. The study shows that reservoir quality of the Qigu formation is better than that of Toutunhe formation. Comparative analysis indicates that the character differences of reservoirs of UpperMiddle Jurassic in study area are compositely controlled by tectonic, sedimentary facies, abnormal pressure and diagenesis, with tectonic evolution being the leading factor. The best microfacies responsible for good physical properties of the Toudunhe Formation is underwater distributary channel while the best that for the Qigu Formation is distributary channel. Abnormal pressures have important impact on preservation of primary pores and position of minerals development. Diagenesis plays a conclusive role in reservoir physical properties, with tuffaceous alteration sequence having important reference value for future exploration of oil and gas.