In this study, the feasibility of alcohol mix fuel (AMF) acetone-butanol-ethanol (3:6:1vol.%) and waste cooking oil biodiesel (WCOB) was evaluated in a dual fuel RCCI engine. AMF and WCOB was used as low-reactivity fuel (LRF) and high-reactivity fuel (HRF) at higher injection pressure (Pinj) (400–600 bar). RCCI operation was optimised at rated load conditions to achieve lower NO and smoke emissions. The optimised results show that AMF injection timing of 8°bTDC, AMF:WCOB ratio 40–60%, and WCOB Pinj 400 bar at injection angle 42°bTDC were observed for optimal performance and emission for the AMF–WCOB RCCI combustion.