Methanol is considered as a promising sustainable, carbon-neutral fuel, and its application in engines faces challenges such as cold start and stringent regulations. On-board hydrogen production through methanol steam reforming, blending with methanol for engine combustion, not only helps to address these issues, but also avoids the storage and transportation risks of hydrogen. However, there is limited research on the effect of mixing methanol with various hydrogen-rich substances on the fundamental combustion characteristics. In this work, the differences in ignition delay time and laminar burning velocity among methanol-methanol steam reforming production (M-MSR) blends, methanol-hydrogen (M-H) blends and methanol-methanol decomposition production (M-MD) blends are investigated through the improved chemical mechanism. Then, the impact mechanism of hydrogen-rich substances on combustion characteristic is revealed by the sensitivity and reaction paths analysis. The results show that at 900 K temperature and 20 bar, 100 bar pressure, as the proportion of hydrogenrich substances increases, the ignition delay time monotonically prolongs due to the decrease in methanol concentration. The ignition delay time of the M-MSR mixture is always the shortest, with the adiabatic flame temperature almost equivalent to that of pure methanol. Moreover, at 600 K temperature and 20 bar pressure, increasing the blending ratio leads to a monotonic rise of the laminar burning velocity, with the smallest gain of M-MSR. Furthermore, a new laminar burning velocity correlation of M-MSR blends is developed for methanol steam reforming-engine co-simulation.