In this paper, We introduce the Interferometric Imaging Radar Altimeter (InIRA), the first spaceborne wide swath ocean radar altimeter on board Chinese Tiangong-2 space laboratory, which was launched on September 15, 2016. The major mission of InIRA is to validate the mechanism and design of new generation ocean radar altimeter, as well as conduct preliminary application researches. The in-orbit observation results of Tiangong-2 InIRA demonstrate that it is capable of measuring the dynamic sea surface height with wide swath, sea waves of different scales and sea winds, which help us greatly improve the observation and measurement efficiency compared with traditional nadir-looking radar altimeters. Besides, it can also be used to survey and monitor the inland waters, e.g. lakes and rivers, as well as acquire terrain digital surface model (DSM). Here, we will present some typical observation results over both ocean and land surfaces.