Abstract: In this paper, the methods of spatial point pattern and Ripley’s K function were adopted to study the spatial distribution, spatial association, and patterncontrolling relationships between Melica przewalskyi and Stipa krylovii in degraded alpine grassland in the upper reaches of Shiyang River, western China, aimed to detect the interspecific patterncontrolling relationships of dominant species during retrogressive succession. Five sampling plots were installed according to the time series, i.e., patch not formed (CK), patch formed (A), patch spread (B), patch stable (C), and patch degraded (D). During the process of retrogressive succession (from CK to D), the spatial distribution pattern of S. krylovii transferred from random to aggregative, and the association between M. przewalskyi and S. krylovii transferred from significant negative to not significant, with the significance decreased after an initial increase. In plots A, B, and C, M. przewalskyi showed patterncontrolling relationships to S. krylovii at 0-15, 0-12, and 0-10 cm scales, but the patterncontrolling relationships did not appear at plots CK and D. By altering microhabitats, the species with bigger size, larger scale, and stronger competition capability forced other species changed their distribution pattern and presented regular distribution, and thus, formed pattern-controlling relationships to other species.