This paper attempts to reveal the influence of using fly ash in the grout on the axial bearing capacity of fully grouted rock bolts. For this purpose, different fly ash contents, including 1% and 2%, have been applied with Stratabinder HS with a water-to-grout ratio of 30%. Also, after preparing and curing the required samples, the UCS tests were conducted to determine the influence of fly ash on the grout strength. Along with the UCS tests, several pull-out tests were examined by preparing and curing rock bolt samples with steel reinforcement rebars of 16 mm and steel pipes with a 50 mm length and 23 mm diameter. The results revealed that replacing a small amount of grout with fly ash could increase the strength of the grout. Also, the axial bearing capacity has risen by using fly ash in the grout mixture.