The large number of fissures developed in loess affect the creep mechanical properties of the soil body, easily triggering geologic disasters such as loess landslides. To gain a comprehensive understanding of the creep characteristics of fissured loess, we used the undisturbed loess from the landslide group in the Heifangtai area of Gansu Province, China, to conduct triaxial creep tests under various prefabricated fissure angles (without fissure, 30 degrees, 45 degrees, 60 degrees, and 90 degrees) and different matric suction conditions. The stress-strain-time characteristics of fissured loess are analyzed, and the long-term strength variation law of fissured loess is determined. The deterioration effect of loess fissures is revealed, and the creep deformation characteristics of fissured loess samples (FLS) are explored. The results show that: (1) The deviatoric stress, confining pressure, and matric suction significantly affect the creep deformation of fissured loess and the duration for the sample to attain steady-state creep. (2) The fissures have a pronounced deteriorating effect on the long-term strength of loess. As the fissure angle increases, the long-term strength of the loess sample initially decreases and subsequently increases, exhibiting a V shaped variation, while the cohesion demonstrates a comparable V shaped variation. (3) The deterioration coefficient of the fissure initially rises and subsequently declines with increasing confining pressure. (4) The creep deformation characteristics of FLS are categorized into axial deformation, bending deformation, and torsional deformation. Generally, the fissure angle affects the axial strain of the sample; however, an increase in confining pressure weakens the influence degree of the fissure on the deformation. The findings provide new insights into theoretical support for the study of loess mechanics and deformation characteristics in the Loess Plateau region of China. This is significant in elucidating the effect of fissures on the occurrence and development of loess landslide disasters.