The invention discloses a common scatter point gather forming method and system for a non-level landform. The method includes a step 1 of inputting a common center point gather of non-level landform seismic data and a root-mean-square speed corresponding to the common center point gather; a step 2 of setting common scatter point gather forming parameters; a step 3 of determining a center point ofthe common scatter point gather and forming a common scatter point gather at a center point position according to the common center point gather, the root-mean-square speed corresponding to the commoncenter point gather and the common scatter point gather forming parameters; a step 4 of repeating the step 3 and forming common scatter point gathers at the center point positions of the all the common scatter point gathers. According to the invention, high covering frequency and a large offset are ensured, and complexity of static correction is reduced. Besides, the method and system can be applied to common scatter point gather speed analysis and equivalent offset directly and development of a new speed analysis and offset method is saved, so that the workload is reduced.