Biocrusts are extensively developed in arid and semiarid climate regions, which cover a large part of land surface with the degraded sparse vegetation. Due to their mulch effects and biological metabolism, biocrusts exert an important influence on almost every ecological process, such as soil water and nutrient cycle, carbon and nitrogen sequestration, soil erosion, biodiversity, and vegetation restoration. Specifically, biocrusts greatly affect carbon exchange and cycling through their photosynthesis and respiration in dryland ecosystems. In arid and semiarid climate regions, the rainfall pattern is expected to be greatly changed due to the acceleration of global climate change, and the change of rainfall pattern will certainly cause the shift of soil water regimes, which fundamentally affect soil respiration. It is widely assumed that biocrust respiration would be affected by the change of soil water regimes, but these effects have not yet been fully investigated. In this study, the impacts of rainfall manipulation on respiration rate of biocrusts were determined through artificially increasing and decreasing ambient rainfall amount by 10%, 30%, and 50%, respectively. The plots with well-developed and moss-dominated biocrusts were established in the Loess Plateau of China, and the respiration rates of biocrusts were measured by a soil carbon flux analyzer (LI-8100A) after the manipulation of ambient rainfall. Our results showed that:(1) the increased rainfall raised soil water content by 17.9%-48.2% in 2018 and by 27.1%-54.2% in 2019. Correspondingly, the decreased rainfall reduced soil water content by 1.8%-26.8% in 2018 and 5.2%-20.8% in 2019. Moreover, the significant (P<0.05) differences were observed in soil water content among the treatments with various rainfall amount and also between the two years. However, the change of rainfall amount had no significant effect on soil temperature. (2) The increased rainfall suppressed biocrust respiration rate by 7.8%-31.7% in 2018 and by 14.7%-39.4% in 2019, but the effects of decreased rainfall on biocrust respiration were dependent on the extent of rainfall reduction. More specifically, the treatments with 10% and 30% of decreased rainfall promoted respiration rate by 27.5% and 9.6% in 2018 and by 23.6% and 9.7% in 2019, respectively; while the treatments with 50% of decreased rainfall lower respiration rate by 15.6% in 2018 and 18.5% in 2019. In addition, all these increasing and decreasing effects on soil respiration were proved to be statistically significant. (3) Both biocrust respiration rate and temperature had a significantly positive correlation (exponential) with rainfall amount; however, the relationship between respiration rate and soil water content was dependent on soil moisture. A linear positive correlation (P<0.05) was obtained between respiration rate and soil water content when soil moisture was <15%, and on the contrary a linear negative correlation (P<0.05) was obtained when soil moisture was >15%. We conclude that the manipulation of rainfall amount has significant impacts on biocrust respiration through regulating their relationships with soil water content and temperature, and these influences should be fully considered in further studying and assessing soil carbon exchange with biocrusts in arid and semiarid climate regions.