A series of stepwise cyclic tests and short-term creep tests were conducted on Beishan granite to quantify the separated effect of stress corrosion and friction degradation during cyclic loading. An opti-acoustic monitoring platform that combined digital image correlation and acoustic emission techniques was utilized to monitor the rock deformation and fracturing at both the micro- and macro-scale simultaneously. In addition, a micromechanical model was built to study the crack growth of rocks exposed to cyclic and creep loads. Experimental and theoretical results indicated that both the repeated and constant loads play a great role in deformation localization, micro-fracturing, and damage accumulation. A similar law was observed in the evolution of the AE b value and distribution of frequency-amplitude in granite under cyclic and creep loading. However, cyclic loads induced a greater AE count rate in granite than constant loads at low loading levels, while constant loads stimulated a greater AE count rate than cyclic loads at high loading levels. Moreover, cyclic loads promoted more strain localization bands than constant load; so, more macro-cracks, branching, and debris were observed in granite during cyclic loading. These similarities and differences indicated that both the stress corrosion and fatigue mechanisms were highlighted to be responsible for the sub-critical crack growth of rocks during cyclic loading. The development of sub-critical crack growth and the evolution of stress intensity factor at the crack tip within rocks under cyclic and constant loads were well described by the micromechanical theoretical model. Highlights: Laboratory experiments were conducted to distinguish stress corrosion and reciprocating wear from rock fatigue. Real-time observation of rock deformation and fracturing was achieved using opti-acoustic technology. A micromechanical theoretical model was built to characterize the sub-critical crack growth in rocks. [ABSTRACT FROM AUTHOR]